Dr. Willis's practice of physick being the whole works of that renowned and famous physician wherein most of the diseases belonging to the body of man are treated of, with excellent methods and receipts for the cure of the same : fitted to the meanest capacity by an index for the explaining of all the hard and unusual words and terms of art derived from the Greek, Latine, or other languages for the benefit of the English reader : with forty copper plates.

THE ANATOMY OF THE BRAIN.

CHAP. I. The Method or Anatomical Administration of Dissecting the Brain is proposed.

AMong the various parts of an animated Body, which are subject to Anatomical disquisition, none is presumed to be easier or better known than the Brain: yet in the mean time, there is none less or more imperfectly understood. All of it that appears, and is commonly descri∣bed in the forepart or forehead, is beheld almost at a sight or two after some rude cutting up; but if you seek what lyes hid in the recesses for that end, new bosoms and productions of Bodies, before hid, are every where laid open: yea the parts of the Brain it self are so complicated and involved, and their respects and habitudes to one another so hard to be extricated, that it may seem a more hard task to institute its perfect Anatomy, than to delineate on a plain, the flexions and Meanders of some Labyrinth: Because, as we are not able to estimate the measure or to paint forth the pattern or draught of the frame of this, so neither of that, unless the bulk or substance of the subject be first searched to the bottom, and its frame broken into pieces. Hence it came to pass, that the old Anatomists in dissecting the Brain, not sufficiently attending what was placed first, what second, and what after that in the order of Nature, cut its Globe as it were into slices or parts, and the Phaenomena arising by chance from such a dissection, they easily esteemed for true parts of the Brain; when yet in the mean time, by others from a dissection otherwise made, the parts and processes of it appear far different from the former. The reason of which is, because the substance or frame of the Brain and its Appendix lyes so within the Skull, that there are many swellings or tuberous risings, with several tails or little feet compacted together: all which, although distinct one from another, and are endued with figures diversly expanded; yet they, that they may be contained in a lesser room, are thrust as it were into the same Globe, and so complicated among them∣selves, that it is a hard thing to find out where the beginning and end of the Brain, as also where the limits and partitions of the near adjoyning parts do remain; further, that the several parts of the Ence∣phalon so complicated, may retain their site, nor presently being loosned one from another, may spring forth, they are knit together into due foldings, with Fibres and Membranes stretched out from part to part. And as often as the substance or bulk of the Brain so conglobated or rolled together is cut, there is as often a necessity that the slips being cut, the portions of divers parts cleaving together, are carried away with them. Wherefore that a true and genuine description of the Brain might be shewed before its substance and continuity is dissolved, before all things its whole frame or substance ought to be explica∣ted, and the knitting of the Membranes being wholly loosned, the several parts ought to be turned over and stretched forth into their proper dimensions. By what means these things may be done, and by what Method the dissection or Anatomical administration of the Brain may be best performed, ought here in the first place to be shewn; then these things being first done, we will more largely deliver the Description of the Brain, together with the use and action of its several parts.

That the perfect knowledge of the Brain and its parts may be gained, it is necessary not only to dissect and look into mens Heads, but all other kind of living Creatures heads; for besides, that the humane Heads or Bodies are not so readily to be had, that one may from day to day behold the Brain and its frame, and carefully consider the situation of the parts, and search one after another their respects, habitudes, and dependencies; besides also the immense bulk of an humane Head is in it self an hinderance, whereby its most intricate frame and various recesses and Appendices are the less accurately discerned and investiga∣ted: all which being reduced into an Epitomy, are plainly represented more commodiously in the dis∣section of Beasts. Wherefore when the form and composition of the Brain in a Dog, Calf, Sheep, Hog, and many other four-footed beasts, were little different (the magnitude only excepted) from the figure of the same, and the disposition of the parts, in a man, I was the more satisfied to compose a certain Ana∣tomy of the Brain by the frequent dissection of all sorts of living Creatures. And in this imployment, for that I shall shew the communities and differences which the subjected parts obtain in various Animals, compared among themselves, and with man; certainly from such a compared Anatomy, not only the fa∣culties and uses of every Organ, but the impressions, influences, and secret ways of working of the sensi∣tive Soul it self will be discovered. Concerning the Heads of living Creatures, in the dissection of which it happened for us chiefly to be exercised, it was observed, as to the chief parts of the Head, that there was a notable Analogy between Man and four-footed Beasts, also between Birds and Fishes: For when the first Inhabitants of the new-made World were produced, as one day brought forth Fowl and Fishes at once, another in like manner Man and four-footed Beasts, so there is in either twin species a like form of the Brain; but between that Child of the former, and this of the following day, there is found a great differ∣ence as to those parts. For as much therefore as Men and four-footed Beasts have got more perfect Brains, and more alike among themselves, we have ordered our Observations from their Inspection: Then af∣terwards we shall deliver the Anatomy of the Brain in Fowl and Fishes. And here first concerning the Heads of Men and four-footed Beasts, (as we hinted but now) we will propose a Method of Dissection it self, or of Anatomical Administration, and will at once recite all the parts one after another, and as it were in a compendious Catalogue; then we will by and by more largely draw out the Particles of the Brain and of its Appendix, so shadowed, in a short Table, and will design their uses and actions for the exercise of every faculty.

When therefore we had in our hands the Head of a Man, or Dog, Calf, or Sheep, its more outward coverings were taken off; concerning which, as they are well enough known, we are not at all solicitous: then the covering of the Skull being divided by a Saw or Instrument, and taken away, on every side the bones are broken off with a pair of Scissers or a Penknife to the Basis of the Skull, that so the Contents might, as much as may be, be all made plain or open to the Spectators. What therefore comes first in view is the hard Meninx including all the rest with a common covering. This Membrane outwardly and above is knit to the Skull in divers places, especially about the Sutures; but indeed about the foot or Basis it most strictly cleaves to the bones, so that it cannot easily be pulled away. Inwardly (or in its hollow superficies) it is lax and loose enough, unless that nigh all its bosoms by the insertions of the Veins, and in the Basis of the Skull by the Arteries and the Nerves it is tyed to the Pia Mater.

This same Membrane between the Interstitia or division of the Brain, and besides of the Cerebel it self insinuating it self deeply on one side, and rising up again on the other, leaves some duplicatures or in∣foldings, in which, being shut up above by the increase of the same Membrane, Cavities, which they com∣monly call Bosoms, are formed: to wit, by this means, almost the three first bosoms are constituted; but the fourth is a smooth and longish, and also hollow process of the same Membrane, which is sent through the Interstitia of the Brain, nigh the end of the callous body, even to the pineal Glandula. The Cavities of the greater Bosoms are severed in many places, as it were into little Cells; as it seems for that end, that the blood passing so through the various turnings in those ends, may be hindred from a more ra∣pid motion.

Besides, this Meninx or Film of the Brain admits two Arteries from either side, one conjugation of which arises not far from the Carotick Arteries through the holes of the Cuniform bone, but the other from the bone of the Forehead: all which indeed being diffused through the exteriour superficies of the Membrane, water it; but are terminated, partly in the Skull, especially nigh the Sutures, whither they convey the blood, and partly in the bosoms, where, what is superfluous is laid up. Moreover, these Arte∣ries perforate the hard Meninx in several places on the top of the Brain (as Webfer observes) and impart some shoots to the Pia Mater. Lastly, the exteriour superficies of this Meninx is no where planted with so many shoots of Veins as Arteries; but from its four Bosoms (which are the veinous Receptacles of the blood) many Veins go out through the interiour superficies of this Membrane, which being inserted in the Pia Mater, are presently dispersed through its whole compass, and the same sliding down on every side from the bosoms, meet every where the Arteries ascending from the Basis of the Head, and being intermingled with them, constitute the manifold infoldings of the Vessels.

That these may be the better beheld, after the Arteries are sufficiently noted, let the hard Meninx be cut round near the border of the broken Skull; then let whatever of it serves for a covering and par∣tition to the Brain and Cerebel, be lifted up, that the goings out of the Vessels, viz. the Veins and their distributions into the Pia Mater may be considered: which being afterwards broken asunder, let the Membrane with its bosoms be wholly taken away; but the reliques of this Membrane,

which stick to the bones at the bottom of the Skull, should be separated, so that the whole frame or substance of the Brain and its Appendix may be somewhat elevated, and moved here and there be every where conspicuous, and at length taken from the Skull. But that these things may be performed, you must begin from the anterior or fore part, where the bone of the Forehead separates it.

Therefore if the prow of the Brain, hid under this bone, be a little lifted up, the mammillary processes come presently in sight, together with the smelling Nerves hanging to them: which being dissected near the Insertion, there will appear an hollowness in either process. These are large and round, also full of clear water in Calves: but in either smelling Nerve a manifest Cavity is found continued on either side to the anterior Ventricles of the Brain, to which if a Pipe be put and blown into, presently the whole sub∣stance of the Brain will swell.

Next the smelling Nerves about the Cocks comb, two small Arteries are seen to arise from the Skull, and to be carried towards the Interftitium of the Brain, which in truth are branches of the Ca∣rotides, which are knit to the dilated Comb before, and from thence are seen to be reflected to the anteri∣or Brain.

These Vessels being there dissected, the coming together and going out of the Optick Nerves follow, the trunk of which being cut off a little lower, the Tunnel, and out of both its sides the Arteries called carotides, arising out of the Cuniform-bone, do appear; which are more clearly beheld, if the Brain be lifted up. These also being cut off, and the Brain farther bent back, the moving Nerves of the Eyes presently shew themselves; and so from thence the other pairs of Nerves follow in order, that one pair of them being cut off, and the Brain with its Appendix more lifted up, the next is still obvious to those beholding it, till all the Nerves arising within the Skull, and also the Arteries, both the Carotides, and the Vertebral being at length cut off, the whole frame of the Head may be taken out of the Skull.

But (that these Vessels may be described in the same order as they are met with in the cutting them up) two small Nerves follow after those moving Nerves of the Eyes, which, for a reason hereafter ren∣dred, we call Pathetick. These Nerves higher than the rest, arising behind two round Prominences cal∣led Nales and Testes, (the Buttocks and Stones of the Brain) and bending down forward, and entring for a little space under the dura Mater, then coming out through the same hole, together with the former, from the Skull, are propagated into the sight of the Eye. This pair is called by Fallopius the eighth, by us the fourth.

Beneath these little Nerves, from both sides of the annulary protuberance, (which being sent from the Cerebel compasses the oblong Marrow) two Nerves of noted magnitude arise, which, after they have passed through the dura Mater, send forth another notable branch on either side straight down without the Skull, the other branch, by a longer tract, passing through both sides the Skull near the Turky Chair. These Nerves (as is shewn afterwards) having gotten a larger Province, are inlarged in the Palate, the parts of the Mouth and Face, and also their branches in the Nose and Eyes, yea they impart roots to the intercostal Nerve. We call this pair t•…•… fifth, commonly esteemed the third.

Nigh to the beginning of these, out of the lowest foot of the oblong Marrow or Pith, two lesser Nerves, endued with a single trunk, arise, which being dilated forward, and presently entring under the dura Ma∣ter, come out of the same hole with the moving Nerves of the Eyes, and are all carried into the balls of the Eyes. This pair is called by us the sixth.

Next to these Nerves follow the auditory or hearing pair, which indeed arises higher from the sides of the oblong Marrow, in what part the Cerebel is hanged to it; viz. nigh the lesser annulary process; from whence it is immediately carried with a double process into the hole of the stony Bone: one of its branches is harder, serving chiefly for motion; the other altogether medullary and •…•…oster, as it were only destinated to sense.

A little lower arises the wandring pair, which is commonly called the sixth. This seems to be made of many Nerves, many of which arise together; and to them comes another, endued with a greater trunk, which being brought from the end of the oblong Marrow, yea beyond this, out of the spinal Mar∣row, is united with the former. And so all being made like a bundle of Nerves, go out •…•…rough the hole of the hinder part of the Head; through which also goes out the greater branch of the in•…•…rnal jugu∣lar Vein. This is by us called the eighth pair.

Under the wandring pair, almost out of the Basis of the oblong Marrow, another pair arises, onsisting also of many Fibres, which going straight down, and being presently immersed in the dura Mate•…•…, comes forth again through a peculiar hole out of the Skull; then either Nerve being inoculated into the trunk of the wandring pair, is presently bended back towards the Tongue. In a man a peculiar protuberance grows above the oblong Marrow, out of which the beginning of this Nerve proceeds. This we call the ninth pair.

Below this, in the lowest part of the hinder part of the Head, out of the sides of the oblong Mar∣row, where it is about to go into the spinal, another pair, consisting also of many Fibres, arises; which tending towards the spinal Marrow, enters the dura Mater at the same place where the Vertebral Arte∣ryascends into the Brain; yet it arises out of the bosoms of the bones, but below the first Vertebra or Joynt, from whence it is carried into the Muscles of the hinder part of the Neck, so that it is doubtful, whether this pair ought to be called the last of the Skull, or the first of the Vertebrals.

When these parts, viz. the aforesaid Nerves and Arteries, both the Carotides and the Vertebrals, with the jugular Veins (by which the Encephalon is fastned to the foot or basis of the Skull) are cut off, and their ends stretched out as much as may be; either let them remain in the taken out substance or frame, whereby the beginnings of all the Nerves may be plainly noted; or the trunks of them being cut off near the roots, may be left in the holes of the Skull, whereby their goings out and distributions may be ob∣served. The images of either Example are delineated in the first and second Table.

The business of Dissection being thus far brought, the residue of the Skull shews many things worthy consideration, of which we shall speak particularly afterwards. But first we ought to view throughly the taken out frame or substance of the Brain, together with its Appendix, and to examine all its appearances as they follow in the order of Dissection.

The substance or Bulk being taken out, which is of a somewhat round figure or spherical it exhibits to the sight in its superiour and convex part the Brain and Cerebel; but the oblong Marrow, with the utmost borders or edges of the superiour bodies, possesses almost all the basis or its lowest part. The thinner Meninx covers these three placed near, and the outward superficies of them all: nor doth it clothe the same loosly, but deeply insinuating it self into all their cavities and recesses, covers and binds them strictly. And as this Membrane is every where interwoven, with the folds of the Vessels, by its stretching out, it reaches the same to every part and portion, and so waters the whole with a sufficient afflux of blood. Here we must consider the Vessels of this Membrane and its protension.

As to the former, the whole superficies of the frame of the subject may be seen, covered with the in∣foldings of Vessels, as it were with a net admirably variegated or flourished, and its sight or aspect shews like the picture of a fruit-bearing wood; the Idea of which, the Vessels of the Brain more aptly represent, and are themselves seen better and more distinctly, if you first squirt into the Carotidick Artery some black liquor. The Vessels interwoven within the thin Meninx or Pia Mater are Arteries and Veins. The Arteries are four, viz. two Carotides and two Vertebrals. Out of either side of the Tunnel the ends of the cut off Carotidick Arteries shew themselves, the trunks of which ascending upwards, are presently dif∣fused from either side into the anterior and posterior, or fore and hinder branch. Either pair of these incli∣ning one towards the other, are mutually conjoyned: moreover, the posterior branches so joyned, are uni∣ted with the Vertebral branches (growing together first into one trunk.) For the Vertebral Arteries, ari∣sing from the last hole but one of the Skull, fall at first divided through the sides of the oblong Marrow; then united in its basis, they go into a single chanel, which meeting with the hinder branches of the Carotides (as it is said) it is joyned with them; and from that place of the joyning of them togethr, a noted branch ascends on either side under the edge or rim of the Brain, which being dilated upon the shanks or stocks of the oblong Marrow, is cleft or divided into very many small shoots like hairs, some of which ascend to the Glandula's placed behind the Cerebel, but the rest make the arterious part of the Choroeidal infoldings. The anterior branches of the Carotides, before they are united, send from themselves on either side a no∣ted branch, which creeping upwards like a bounding River, distinguishes either Hemisphere of the Brain as it were into two Provinces; but after the aforesaid branches are united, presently departing again from one another, they are carried to the Prow of the Brain, and from thence bending back between its Hemi∣spheres, they fall upon the callous body. All these Arteries, before and after their mutual joyning toge∣ther, send forth shoots and little branches on every side, which do not only creep through and intimately bind about the utmost compass of its Sphere, but its Penetralia, and more inward recesses, like the young branches of Vines. The ramifications or these sorts of branchings, both of the Carotides and of the Vertebrals, are shewn in the first Table as they are found in a Man, and as a Sheep in the second Table.

Moreover, this thinner Meninx or Pia Mater, cloathing the whole Brain, and its parts, as it receives the Arteries ascending (as hath been said) from a four-fold Fountain, so it is stuffed throughout with Veins, sent from four bosoms. These Vessels mutually meeting, are complicated together, and almost every where constitute by their branches derived from both, and meeting one the other, and variously contorted among themselves, the net-like or retiform infoldings; which indeed are not only outwardly in the superficies, but in the dissection, where-ever you may separate one part from another, without breaking it, these kind of infoldings of the Vessels are to be found. Because, if you behold this frame, taken out of the Skull, col∣lecting together the tops of all the turnings and the Interstitia in this Membrane, and covering them with the joynings of the Vessels, it will make the whole compass or frame of the Encephalon appear like a curi∣ous quilted ball. But if you go on to cast abroad this Sphere, and to separate the cleaving parts, knit toge∣ther, of this Membrane, one from another, you will soon find, that this Meninx covers the gapings of the crevices or turning chaps of the Brain, binds the Interstitia of either moiety or Hemisphere, draws toge∣ther the hinder part of the Brain, otherwise being lax and hanging loose, and compassing about every border of it, as it were with a Welt, knits it to the oblong Marrow: and what is the chief of all, the universal Cor∣tical or shelly substance of the Brain (to wit, in which the animal Spirits are procreated) is covered over with this Membrane planted with most frequent infoldings of the Vessels; notwithstanding the interior su∣perficies of the Brain being stretched out, (which being called the Callous body, is altogether medullary and white) is not cloathed with this Membrane: but instead of it many foldings of vessels, commonly called Choroeides, are hung and as it were freely flow within its complicature. The reason of which is, because as this part, to wit, the callous body, is rather designed for the Circulation than for the generation of Spirits, therefore it admits not a more plentiful influx of blood: nevertheless, for as much as there

is need of heat, whereby the Spirits may be there more easily circulated, the blood being moved, within the Vessels hanging there through the empty space, might af•…•…ord heat as it were from a fire kindled within a Stove. But within all the other recesses of the Brain, and besides, within the folds or lappets of the Cerebel, yea, and the Interstitia or gaps of both these, and of the oblong Marrow, this Meninx insi∣nuates it self, and inserts the distributions of the Vessels. In truth, the protension or out-stretching of this Membrane seems therefore the more admirable, because having no where a peculiar place of its ori∣gine, it not only binds about the Head or Encephalon with a common covering, but also cloaths all its parts with proper coverings, and knits together their tops and processes. Yea, this Meninx seems to enjoy a manifold and divers original: for where-ever the gapings or Interstitia of any parts or processes happen, portions of this Membrane there springing forth, cover them all, and gather them together, and reach to them the ramifications or branchings of the Vessels. In a moister Brain this Meninx may be easily sepa∣parated, and ample and large portions of it pulled away with the fingers; which being drawn away, the insertions of the Vessels, into the substance of the Brain and its Appendix, every where clearly appear. Lastly, by this means the brain being thus left naked, unclothed of its Membranes and Coverings, its make or fabrick, and the disposition or order of all its parts are next subjected to Anatomical Inspection.

That the Anatomy of the Brain, properly so called, might be rightly celebrated, I judge we ought not to proceed after the common way of Dissection. But when as the substance of the whole Head, ta∣ken out of the Skull, stands in view, first let the hinder partition of the Brain, where it is knit to the Cerebel and oblong Marrow or Pith, the Membranes being every where cut or pulled off, be freed (as much as it may be) from its cleaving to the subjected parts; then it will easily appear, that the substance of the Brain is not united to those bodies, but of it self is altogether free and independent of them, unless where it is joyned towards the superficies by the knitting of the Membranes. Also this keel or hinder part of the Brain being divided by this means from the neighbouring parts, if the fore-part be bent back, the shanks of the oblong Marrow will appear wholly naked, and distinct from the Brain and Cerebel (un∣less where they are in some places hung to it.) Moreover, when the partition of the Brain, being loosned from its cohesion, is lifted up, the three Ventricles, commonly so called, go into one empty space or mere vacuity, resulting from the complication of the Brain. Besides, it may be observed, how the Brain before is only united to the oblong Marrow; and that in two places of its shanks, as it were the tops, it is fixed; which Fornix so called, or arched Vault, is as it were a string or ligament, which arising before, where the Brain is hanging to it, is carried to its hinder border, to which it is united as it were with two stretched out arms, and so it holds together the whole frame of the brain, lest it be rolled out into a plain, still in a spherical figure, and firmly binds the same to the shanks of the oblong Marrow. From the knitting o•…•… the other parts of the humane brain divided and lifted upwards, whereby the vacuity resulting from its infolding, and esteemed for Ventricles, also whereby the Fornix or arched Vault and Shanks of the ob∣long Marrow, naked and distinct, may be beheld, is represented by figure in the fourth Table.

And truly, this Position or Aspect of the Brain, to wit, when its hinder border or partition, being freed from its cohesion by the Membranes to the oblong Marrow, and elevated, is bent forward, exposes to be seen by the eyes themselves, its whole frame or substance, to wit, whatever it hath without or within, or before and behind, and also plainly detects what its habitude and respect is to the other parts. The chief things of these I shall add, and in the same order wherein they occurred to Inspection.

The figure of the Brain, especially in a man, shews somewhat globous or spherical: the outward su∣perficies is on all sides noted with chinks turning and winding like to the rollings about of the Intestines: each breach or Involution, yea the whole circuit of it contains a twofold substance, viz. the Cortical or rindy, which is the outmost and of an Ash-colour; and the medullary or marrowy, which lyes under it, and appears white. The Brain being as it were plowed with these kind of rollings about, like so many ridges and furrows, is cleft in the middle, and parted as it were into two Hemispheres; yet both the moities come together, and are as it were founded in one like white substance, which covers inwardly, and as it were in Chambers or Vaults, the whole bulk of the Brain. This is harder than any other portion of the brain, and as it is altogether medullary; it receives all the marrows of the circumvolutions within it self, and is to them instead of a common basis. In either Hemisphere of the Brain, about the fore parts, this callous body or marrowy substance, becomes more firm and thick by far than in any other place; and there it is on both sides fastned to the tops of the oblong Marrow. From those tops, as it were its beginning, this medullary substance, covering over or chambering or arching the Brain, is stretched out towards the hinder parts, and by degreeslessens in its thickness: at length the outward border of this stretched out, is drawn together more narrowly, and more below, it is conjoyned by the knitting of the Mem∣branes and Vessels (as we but now mentioned) to the tail of the oblong Marrow. Besides, for its more firm connexion, a medullary process arises from the fore part of the callous body towards the tops of it, which stretching under the fissure or cleft of the brain, reaches to its border; to which it is united, as it were with arms bending on either side: which arms indeed embrace the tail of the oblong Marrow, and so more firmly knit to it that border of the Brain.

This medullary process, commonly called the Fornix, under its rise or beginning, hath two white and medullary roots, either of them alike going out from the callous body, which roots nigh the tops, where the brain is hung to them, meeting together, pass into the Fornix or Vault it self, as if it were a broad process, which stretches under the chamber of the brain, like a beam. Under this twofold root of the For∣nix is laid cross-wise, of the same magnitude, a medullary trunk, by which, like a bridge, there is a certain passage and communication between two processes of the form of a Lentil, and chamfer'd or furrowed bodies beaming or shining in them. Further, from the midst of the superficies of this Fornix, a thin and pellucid hedge or pale is erected, which is affixed to the chanel or furrow of the callous body, al∣most along its whole passage. And for this reason, whilst the three-sided Fornix stretched underneath a chamber, arising from the complication of the brain, it distinguished its appearing cavity as it were into three partitions, and so caused, that in it three Ventricles were represented.

The interior recesses of the Brain will lye yet more clearly open, if the border, being on every side sepa∣rated and lifted up, as much as may be, from its cohering with the oblong Marrow, be cut a little fur∣ther through the substance at the sides of the same Marrow, to which it is united, nigh the chamfer'd bodies, and also the Fornix, being cut nigh the roots, be bent back, together with the brain; for then the frame of the brain may be wholly lifted up, turned forward, and unfolded into a plain, so that the whole interior superficies of the callous body being stretched out into a broad floor, may be seen and han∣dled. Where, besides the medullary, and its most white substance, may be observed many white paral∣lel lines, which cut the partition of the Brain in right angles, as if they were certain tracts or footsteps, in which the animal Spirits travel from one Hemisphere of the Brain to the other, and return back again.

After this manner, in very many perfect four-footed Beasts, the frame or substance of the Brain was wont to be turned over, the Sphere being projected into a plain, and its interiour superficies to be un∣folded into breadth. Also this kind of Method of Dissection may be used in a mans brain, where the same Phaenomena wholly occur to Anatomical observation. The chief difference is, that the bulk of the brain of a man, for that it is very large, and also far thicker, and endued with more turnings and wind∣ings; therefore it cannot be so easily and throughly inverted, as that of a Calf or Sheep, and reduced into a broad plain: yet it may be so far expanded and lifted up near its border or partition, that all the interiour recesses may appear in view. The third and Fourth Figures shew the image of an humane brain bent back; but in the seventh Table is shewn the aspect or sight of a Sheeps brain wholly unfolded, and as it were spread plain.

In the lesser four footed Beasts, as a Mouse, an Hare, Coney, and some others, the superficies of the Brain being wholly plain or even, wants the turnings and windings; however from the compli∣cation of the border, and the under-stretching of the Fornix, there results a cavity representing Ventricles.

After that we have throughly viewed all things which belong to the Brain, in the order as we have said, let either Hemisphere, covered within with the callous body, by which it hangs, be divided and removed from the tops of the oblong Marrow: which indeed may be exactly done, by cutting it near to the sides of the Lentiform prominencies, which are found in the vulgar dissection of the Head, within the interior Ventricles: for those prominencies are the tops or heights of the shanks of the oblong Mar∣row, to which the callous body is immediately fixed. When the brain is cut after this manner, that the prominencies, which are the tops of the shanks of the oblong Marrow, may be left naked, let them be cut long-ways through the midst (to wit, in the medullary part, where they are conjoyned to the callous bo∣dy) and their interior substance will appear through the whole chamfered or streaked; viz. medullary streaks or chamferings are seen to ascend and descend forward and backward; that none may doubt, but that these chamferings or streaks were made by Nature, as it were passages or chanels for the passage and return, or going to and fro of the Spirits out of the callous body into the oblong Marrow, and on the con∣trary. The Figure of the shanks of the oblong Marrow, divided from the Brain, with their tops, which are the chamfered bodies, is expressed in the eighth Table.

After these striated or streaked bodies, the shanks of the oblong Marrow being divided for a little space, go forward, then being united, they meet together in the same stock, made up as it were of two stems. But the stock or trunk of the oblong Marrow in its whole tract, viz. before and after the coalition of its shanks, hath many Processes, Appendices, Prominences, and Insertions of Vessels, some of which arise from one side, and others from the other side, and make it unequal, with various productions and protuberances; of which hereafter.

[illustration]

Fig. I.^a

[illustration]

Fig. II.^d

B B. p. 51.

The First Figure.

SHews the Basis of an humane Brain taken out of the Skull, with the Roots of the Vessels cut off.

• AAAA. The anterior and posterior Lobes of the Brain quadripartite or divided into four parts.
• BB. The Cerebel or little Brain in the hinder part of the Head.
• CC. The long Marrow or Pith.
• DD. The smelling Nerves or the first pair.
• EE. The Optick or seeing Nerves the second pair.
• FF. The moving Nerves of the Eyes the third pair.
• GG. The pathetick Nerves of the Eyes, or the fourth pair.
• HH. The fifth pair of Nerves.
• II. The sixth pair of Nerves.
• KKKK. The auditory or hearing Nerves, and their two processes on either side of them, the seventh pair.
• LLIIII. The wandring pair, or the eigth pair, consisting of many Fibres.
• MM. The Spinal Nerves coming from afar to the origine of the wandring pair.
• NN. The ninth pair consisting also of many Fibres, (which tending downwards, grow together into one Trunk) which arises a little above the process of the hinder part of the Head.
• OO. The tenth pair tending downwards.
• PP. The Trunk of the Carotidick Artery cut off where it is divided into the anterior and posterior Branch.
• QQ. A Branch of it going in between two Lobes of the Brain.
• R. The anterior Branches of the Carotides go away united, moving forward into the fissure or cleft of the Brain.
• S. The posterior Branches of the Carotides united, and meeting with the Vertebral Trunk.
• TTT. The Vertebral Arteries and their three Branches ascending.
• V. The Branches of the Vertebrals growing together into one Trunk.
• WW. The place designed where the Vertebrals and the Carotides are united, and either Branch ascends to the Choroidal infolding.
• X. The Tunnel.
• YY. Two Glandula's or Kernels placed behind the Tunnel.
• aaaa. The annulary Protuberance, which being sent from the Cerebel, embraces the stock of the long Marrow.

The Second Figure.

Shews the Basis of a Sheeps Brain taken out of the Skull, and the Roots of the Vessels cut off, where all the Ar∣teries, by Ink being injected into one of the Carotides, are made black and more conspicuous.

• AA. Two Hemispheres of the Brain without Lobes, different from that in a Man.
• BB. The lateral portions of the Cerebel.
• CCC. The oblong Marrow.
• DD. The olfactory or smelling Nerves cut off nigh to the mammillary Processes, that their Cavities may appear.
• E. The Coalition or joyning together of the Optick Nerves.
• FF. The motory Nerves of the Eyes, or the third pair.
• GG. The Pathetick Nerves, or fourth pair.
• HH. The fifth pair: the Trunk of which Nerve is presently divided into two Branches.
• II. The sixth pair.
• KK. kk. The seventh pair, or the hearing Nerves, on either side of which are two Processes.
• LL. The eighth or wandring pair, the origine of which is made up of very many Fibres seeming to grow together.
• MM. A Nerve coming out of the spinal Marrow to the beginning of the wandring pair.
• NN. The ninth pair, consisting also of divers Fibres arising distinctly, which afterwards grow together into one Trunk.
• OO. The tenth pair tending downwards.
• PP. The Trunk of the Carotidick Artery cut off, where it is divided into the anterior and posterior Branch.
• QQ. The inosculation of the anterior Branches.
• R. The posterior Branches of the Carotides united, and meeting with the Vertebral Trunk.
• SSS. The Vertebral Artery ascending with a triple Branch.
• TT. Where the Carotides meet the Vertebral, and on either side many Arteries ascend to the Choroeidan infold∣ing.
• V. The coalition or joyning together of the Vertebral Branches into the same Trunk.
• W. The Tunnel.
• X. A white Glandula or Kernel placed behind it.

CHAP. II. The Parts of the oblong Marrow, and the rest of the hinder Parts of the Head are recounted, and their Dissection shewn.

HAving described both the Meninges, and the ramifications of the Vessels in them, also the fa∣brick of the Brain, properly so called; and next shewed its outward partition gathered toge∣ther into folds about the shanks of the oblong Marrow, and either middle or marrowy part of it hung to the chamfered bodies; we will now follow the remaining parts of the Head in order.

The chamfered or streaked bodies, or the tops of the oblong Marrow, are two lentiform Prominen∣ces, which are beheld within the former Ventricles of the Brain, as they are commonly termed; the heads of these, which are more large and blunt, incline mutually one to another, and are almost conti∣guous. Out of the angle of this inclination the Fornix arises with a double root; to which is subjected or underlaid a certain transverse medutlary process, and seems to knit together these streaked bodies, as may be seen in the seventh TableGG. but the ends of those bodies, being made sharpes, are reflected out∣ward, and make as it were two sides, with a sharp triangle, to whose anterior superficies the marrow of the callous body sticks for a long tract; where, if these bodies be cut long-ways through the midst, the medullary streaks (as was already said) will presently appear. The figure and place of these, as also the medullary chamferings, are truly represented in the eighth Table.

Where the streaked bodies end, the chambers or Thalami, as they are termed, of the Optick Nerves, possess the next part to the oblong marrow; to wit, in this place, its shanks rise into unequal protube∣rances, out of the ridges of which the Optick Nerves arise, and from thence, being bent down in the fore-part with a certain compass, they joyn together about the base of the same marrow, and seem to be united; by and by being again parted, and going forward towards the ball of the Eye, they go out of the Skull. In this place the shanks of the oblong marrow in a Man are for the most part distinct, and gaping one from another, leave a descending opening, which is in the passage to the Tunnel; but in most four-footed Beasts the shanks of the same medullary stocks are there distinct, only a little low∣er, and have a chink cut for the Tunnel: but the ridges of them, in which the beginnings of the Optick Nerves lye hid, are somewhat conjoyned, and for the space of half an inch do grow together. Wherefore in Brutes there is one hole before this growing together, and another behind it, both which lead towards the Tunnel. The reason of this difference is, because in a Man, for that the frame or Substance of the brain it self is very large, and that its marrowy parts are remote one from another, it is behoveful for its shanks, whereby the tops of the oblong marrow may be the better fitted to the fame, to be separated, and from their mutual touching to be bent into a greater aperture. Hence it is observed, that in a Man the shanks of the oblong marrow, from the hanging on of the Brain, go forward with a greater angle of inclination, and with a certain bending compass; but in Brutes the same lye almost parallel. After what manner these parts are formed in an humane brain the third and fourth Figure shews; after what manner they are in four-footed Beasts is shewn in the seventh Figure.

From the same ridges of the medullary shanks, from whence the Optick Nerves take their origines certain medullary processes arising, and being dilated on either side above the brim of the second hole, grow together about the root of the pineal Glandula. These processes (as it seems) are those parts, which the Famous Cartes supposes to be Nerves belonging to the pineal Glandula: but I rather suspect them to be productions only, by which the Optick Nerves may also communicate near their origines. Their figure is very well described in the seventh Table.

After the Thalami or Chambers of the Optick Nerves, other notable protuberances; commonly called Nates and Testes, the Buttocks and Testicles (of the brain) grow to the superior part of the medullary Trunk or stem, and cover its superficies about the space of an inch; and for that they are not contigu∣ous in the midst, there is under them a certain hollowness in their whole tract. These protuberances are lesser in a Man, also in a Dog and Cat; lastly, if we observed rightly, in other living Creatures, which are newly brought forth, that are impotent, and not instructed for the finding out of food. In a Calf, Sheep, Hog, and the like, they appear far greater: in Fishes and Fowls they are wholly want∣ing.

In number they are four, viz. two grow to either side of the oblong marrow. The former called Nates or the Buttocks, seem the greater and principal; to which the other latter called Testes or the Te∣sticles, hang as if growing out of them. As to their figure, they are round, and are commonly taken for two shanks on either side of the Brain and Cerebel planted near, which being bent inwardly, and turned back one towards the other, are said to grow together, and so to constitute the oblong marrow. But this opinion, as we shall shew more largely hereafter, by the dissection ordered according to our Method,

is clearly false. For it plainly appears, that the Brain is fixed, long before these bodies, to the oblong marrow; not is there any commerce between these and that, unless very remote.

But if the site of these parts, and their respects and habitudes to the neighbouring bodies, be well noted, it will appear plainly, that they make as it were a certain peculiar Region wholly di∣stinct from the Brain and Cerebel, also from the oblong marrow it self. Their situation is re∣mote enough from the fore-parts, and sufficiently separated by the Cavity or Ventricle under-lying from the medullary stock or stem: yea a proper way, or one process, seems to lead from the long marrow into these prominences, and another to go from them, and thence to be carried into the Ce∣rebel. From hence we may suspect, that these prominences (especially the Native-form, or of the shape of a Buttock, which are the chief) are certain places of diversion, in which the animal Spirits go apart in their passage from the oblong marrow into the Cerebel, and from this to that on the other side, and there stay for some animal uses, of which we shall speak hereafter. As to the way, which leads from the oblong marrow into these prominences; it is manifest, that beneath the ori∣gines of the Optick Nerves on either side a medullary Process descends, with little Villages proper for it self, which terminates in the aforesaid prominencies. Then, if from these, you look for a passage out, it is equally clear, that from the hindermost prominencies, which are called Testes, on either side, a medullary process doth obliquely ascend, which being dilated into the Cerebel, is di∣varicated through its whole frame. But that the Natiform or Buttock-formed Prominences are Principals, and the Testes their dependences, or the heads of medullary Processes, which are carried from thence into the Cerebel, manifestly appears in a Sheep, Calf or Horse, and in some others, where the Nates are of a noted magnitude, the Testes of a very small bulk grow to them, and in the middle between these the medullary Processes, the Appendices of the former Prominences, exist. The aforesaid Prominences, as also the medullary Processes, which lead forward and backward, to and from them, are aptly represented in the fourth Table, but yet more clearly in the eighth Table TT. PP.

Further, because the Animal Spirits residing in either Promptuary and Appendix, before they are carried to the Brain, ought to be confounded and mingled together, therefore the two promi∣nences of either side do mutually grow together as it were with wings stretched out one to another; but for as much as it is behoveful for those growings together to be distinguished from the oblong marrow, therfore an hollowness comes between, which is by some esteemed the fourth Belly, and by others a passage to it. These Prominences in a Man, Dog and Cat, and some other Animals (as was above mentioned) are very small; and almost even; also they appear, as the other porti∣on of the oblong marrow, of a white colour. In a Calf, Sheep, Horse, and many other four-foot∣ed Beasts, the former protuberances, commonly called Nates or Buttocks, are remarkably great, also outwardly they appear to be of a flesh-colour, because they are cloathed with the thin Meninx or Pia Ma∣ter, which contains in it self very many Veins and Arteries; which if separated, the interior sub∣stance of those parts is of a wannish colour, and such as is not in all the oblong marrow or pith besides. But it plainly appears, as in Brutes, so in Man, the hinder or posterior prominences are Epiphyses or additions of the former, and that from these additions or dependences the medullary processes ascend obliquely into the Cerebel; near which, other processes cutting those, descend direct from the Cerebel, which seem not to be inserted into the medullary Trunk, but going about it, do con∣stitute the annulary or ringy protuberance. This annulary protuberance is greater in a Man than in any other Creature. Besides, it is observed, that where-ever the superior prominence of the Buttock∣form is larger, this inferior annulary is very small; and so on the contrary. Further, those medul∣lary processes, ascending towards the Cerebel, communicate mutually among themselves by the other transverse medullary process; and out of this tranverse process, two small little Nerves arise, the fourrh pair of those which we have recounted, and which are called by us Pathetical. Each of these, delineated in fit figures, the seventh Table shews clear enough.

Not far from the aforesaid Prominences, to wit, between these and the Chink, which is called the Anus or Arse-hole, the Pineal Glandula or Kernel is placed, This is put in a Valley, which lyes between the Natiform protuberances, and those which are the Chambers or Thalami of the Optick Nerves; in which place that Glandula on Kernel is fixed, sometimes by very many small Fibres, and sometimes by two noted medullary roots subjected to the part; and besides it is included in a Membrane, which is a portion of the Pia Mater, as in a Chest; and as this Membrane is stuffed with ve∣ry many Arteries and Veins, some small Vessels also enter into this Glandula.

Under the Prominences but now described, (as was above hinted) a narrow Cavity or Ventricle is stretched out with a long passage, which, although it obtains some egregious uses, yet it self seems to be only secondary, and as it were by chance; for that the processes of either prominence ought to be conjoyned among themselves, and to be distinguished from the under-lying medullary Trunk. Two holes lye open into this Trunk, one of which is placed in the beginning, and the other in the end of it, and through the middle of its passage the down-bending aperture tends towards the Tun∣nel; so that the serous humor entring at either hole, may presently slide away into the Tunnel. Moreover, into the same aperture of the Tunnel there lyes open another passage, to wit, through the first hole which is placed near the roots of the Fornix; so that from every quarter of the Head the se∣rosities

might be carried into that sink; to wit, that through the first hole, from the infoldings or the anterior Ventricles of the Brain; through the second hole, the humors which are gathered about the orbicular prominences, do •…•…ome away; and through the third hole, those which are laid up nigh the confines of the Cerebel, do find a passage. These several holes, with the distinct ways to the Tunnel, are plainly delineated in the seventh Table H. M. T.

Above the Pineal Kernel, as it were above the Button, the infolding of the Choroeides seems to be hung; now this infolding is made after this manner: out of either side of the oblong marrow, where the border of the Brain is knit to it, two Arteries arising from the posterior branches of the Carotides, where they are united to the Vertebrals, do directly ascend; which being presently divided, like many Rivers planted near together, are carried towards the pineal Glandula, and there seem to be terminated by a mutual meeting: and in that place, out of the fourth bosom, sent down upon the pineal Glan∣dula, the veinous branches come out on both sides, which in like manner being divided into fila∣ments or small threads, meet with the capillary or hairy Arteries, and are in many places inoculated into them, and variously complicated with them; and so these Vessels, being Net-like, much interwo∣ven among themselves, and interserted with the Glandula's, do constitute the to be admired infoldings. These kind of infoldings of the Vessels, as it were with two out-stretched wings, are thrust out on either side upon the shanks of the oblong marrow, even to the streaked bodies; but yet they only lye upon their superficies, nor are they more firmly affixed either to the oblong marrow, or to the callous body by any insertions of the Vessels; so that the blood seems only to be brought to these places, and carried away without any afflux of it made into the subjected parts; for what uses shall be spoken of hereafter. The Choroidal infoldings, with the pineal Glaudula, are drawn out in the seventh Ta∣ble. G. F. E.

And thus far concerning the appearances found above the oblong Marrow, between the streaked bo∣dies and the Cerebel; which indeed are almost constantly after a like manner both in Man and four∣footed Beasts, unless that they only differ in bigness. Within this space, in the Pedestal or Basis of the same Marrow, many things worth noting occur: For besides the ends of the cut off Vessels, which are above recited, the site and structure of the Infundible or Tunnel deserve consideration. For behind the coalition or joyning together of either Optick Nerve between the shanks of the oblong Marrow there gaping, is sent down a receptacle as it were tubulated or made like a Pipe, covered without with a thin Membrane arising from the Pia Mater, and desended within with a medullary substance. The orifice of this is placed higher, between the shanks of the oblong Marrow, and receives their bending aperture; from thence a short Tube or Pipe being sent down, is inserted to the pituitary Glandula or Kernel. We see this Tube in an Horses Brain greater than a Gooses Quill, also shining and full of clear water; that it is not to be doubted, but that by this way the serous humors slide away from the Brain to the pituitary Glandula: but how these humors are carried away from thence, shall be after∣wards inquired into, because they are not carried into the Palate or Roof of the Mouth, as is commonly believed.

Nigh the lower border of the Tunnel, in a Man, underneath there are two whitish Glandula's, though in Brutes only one, but greater, is found. What is the proper use of this part shall be told hereafter: in the mean time, whether it be doubled or only one larger, it seems to be as it were instead of a bank to defend or preserve the thin Membrane of the Tunnel, lest it should be broken or thrust out of its place: on the other side the growing together of the Optick Nerves serves instead of the same kind of de∣fence.

What besides is contained in this space are only the shanks of the oblong Marrow it self, which pro∣ceed directly from the chambers of the Optick Nerves towards the hinder part of the Head in a straight passage; and when both grow together below the Tunnel, they are afterwards distinguished in their whole tract by a line drawn through the midst. These shanks of a mans Brain are far larger than in brute beasts; to wit, in that they seem to be made up of very many medullary cords or strings joyned together in one, as if in this common passage and high-way of the animal Spirits, they were so many di•…•…tinct paths, which the Spirits enter into respectively, according to the various impulses of sense and local mo∣tion. Moreover, this space of the oblong Marrow therefore appears shorter and more broken in a man, because much of it is hid by the annulary protuberance, which is sent from the Cerebel, and is very big. The Pia Mater, all about covering the sides of this medullary Trunk, cloaths them with most thick in∣foldings of the Vessels; by which heat and the nervous juyce are carried, as a continual provision for the Spirits, taking a long journey. Thus much for the first Section, or anterior portion of the oblong Mar∣row: now our order carries us to the inspection of its hinder Region, to wit, where the Cerebel grows to it; and the Processes sent from this either compass about its Trunk, or are inserted into it; out of which also, the other Nerves produced within the Skull, take their beginnings. Concerning these we will speak in order.

CHAP. III. A Description of the Cerebel and it Processes, also of the hinder Region of the oblong Marrow.

BElow the orbicular Prominences, the Cerebel follows to be inspected. The figure of this, like the Brain, is somewhat globous, also it appears unequal, marked with certain turnings and windings about; the ridges and furrows of whose turnings about the Pia Mater stretches over, and reaches out the infoldings of the Vessels to them all, and deeply inserts them into all. However the Cerebel is diversified or variegated with its turnings and rollings about, not as the Brain, after an uncertain man∣ner; but its folds are disposed in a certain orderly series; for the exterior frame of it seems to consist of thin lappets, or little rings or circles, being contiguous and infolded, also going about through the whole compass with a parallel site or situation.

Either Region of the Cerebel, to wit, the former and the hinder, is terminated in a process in form of a Worm. According to these ends, as it were in a double Pole, these Circles are very short; thence ascending towards the top or Equator, they are by degrees enlarged, as it were Parallels in a Sphere or Globe. These Circles are outwardly Cortical or barky, and within medullary, and all their marrowy parts pass into two ample middles; which indeed seem to be the same in the Cerebel, as the callous body in the Brain.

The Cerebel in some Animals consists of one frame, and all its little circles are placed in the same pa∣rallel site, and keep the same proportion among themselves; but in others there grow to the Cerebel as it were the primary Sphere, and endued with greater circles, some other bodies as it were Wens or Ex∣tuberances, or additional Spheres marked with lesser circles. These being eccentrick to the Cerebel it self, have oftentimes labels or folds ordered in a diverse series from it.

But the Cerebel it self (whether it hath these little Excrescences growing to it or not) is found al∣most in all Animals of the same figure and proportion, also made up of the same kind of labels or lap∣pets. Those which have the Brain diversly framed from a Mans, as Fowl and Fishes, also among four∣legged Creatures, Conies and Mice, whose Brains want turnings about or convolutions, have the like species and the like disposition of the folds and composure of the other parts of the Cerebel. The reason of this difference in the brain, and of the conformity in the Cerebel, is rendred hereafter, when we treat of the Use of the Parts.

As the Brain, within its Cavity, hath the Choroidal infolding made up of Arteries and Veins vari∣ously complicated, and of Glandula's thickly interserted; so also the Cerebel hath got the like infoldings of Vessels, and those marked with very many Glandula's, and greater than those in the Choroidal in∣folding. These infoldings and heap of Kernels, the Pia Mater being separated, which clothes the hin∣der part of the Cerebel, easily appear in sight; for in that place these creep upwards on eithe side nigh the Worm-shaped process, as it were with two branches; and receive the Artery on either side, from the Vertebral Artery, lying under the Basis of the oblong Marrow and the veinous passages, sent from ei∣ther lateral bosom. We shall inquire hereafter into the use of this Infolding and ofits Glandula's.

In the mean time, that we may describe the site and hanging on of the Cerebel; the same standing on the oblong Marrow seems to be fixed to its sides, as it were by two little feet; between which, planted on either side, and the Cerebel placed above, and the trunk of the long marrow below, (because all these should be distinct one from the other) there comes a cavity or hollowness between, which is commonly called the four Bellies.

In either little foot, sustaining the Brain, are found three distinct medullary Processes. The first of these, sent from the orbicular Protuberances, ascends obliquely; the second descending straight from the Cerebel, and passing through the other across, compasses about the oblong Marrow; the third process, descending from the hinder Region of the Cerebel, is inserted into the oblong Marrow, and increases its trunk as it were with an additional cord or string. These several Processes are truly represented in the seventh Table. Q.P.R.

But as to what belongs to the annular or ringy Protuberance, by which the medullary Trunk, both in Man, and in some four-footed Beasts, is compassed about, that is made after this manner. The second or middle process of the Cerebel, descending straight to the oblong marrow, seems not to be implanted in it, as soon as it touches its sides, but growing into a larger bulk, goes about the superficies of the same Marrow with divers circular Fibres. And so when in either side both those kind of processes of the Ce∣rebel, being dilated or carried from the top of the medullary Trunk towards its Basis, do mutually meet, they make that circular protuberance. The substance of this is far larger in a Man than in any other Ani∣mal, in an Hare, Rabbet, Mouse, and the like, it is very small; in Fowl it is either wholly wanting, or for its smallness scarce to be discerned by the eyes. Concerning its bulk, this is a constant observation. They who have the orbicular prominences before the Cerebel small, have this annulary protuberance very big; and on the contrary, they who have those prominences big or very great, have this ring very small: further, they who wholly want the Buttock-form protuberances, as in Fowl, seem also to want this annulary.

In many brute Animals, but not in Man, nigh to this greater Protuberance, a little lower, another les∣ser, in like manner orbicular, stands, and compasseth about the superficies of the oblong Marrow; the root of which is a white and medullary line, stretched out under the Cerebel, above the botom of the fourth Ventricle. From the sides of this lesser protuberance the auditory Nerves arise: In Man the auditory or hearing Nerves are seen to arise out of the utmost brim of the greater protuberance, in like manner they have for their root a white medullary line covering the fourth Ventricle.

That this line, and the three distinct medullary Processes, which constitute either little foot of the Cere∣bel, may be more plainly shewn, also that the most inward frame of the Cerebel may be viewed, its whole Globe ought to be cut through both Poles, viz. in the middle through the Vermiform or Worm-shaped processes; then it will plainly appear, that in either Hemisphere there is an ample middle or marrow, wherein the marrowy branches, being stretched abroad on every side, like those of a tree, spread through the Cortical substance of the Cerebel, every where diffused; and that in either middle or marrowy part, the three distinct processes, which make either trunk, or little foot of the Cerebel, are inserted. Each of these, are fitly represented in the seventh Table.

Thus much for the Cerebel, and by what means it is fastned to the oblong marrow. Beside these it is to be observed, that about the bottom of the Basis of the oblong marrow, out of the greater Ring, come out two medullary strings, which being distinct from the rest of the medullary Trunk, go right forward to∣wards the spinal marrow, and in its progress, being made straiter by degrees, like Pyramids, after about the space of an inch, end in sharp points. The extremities of these consist on the other side, where the wandring pair of Nerves have their original, and make a certain rising up in the oblong Marrow. Hence it is likely, that these strings are passages or chanels of the animal Spirits, wherein they are carried from the greater Ring, or what is the same thing, from the Cerebel into the wandring pair, and the beginnings of other Nerves implanted near; for what end, shall be said herea•…•…ter. These pyramidal B•…•…dies do not so manifestly appear so long as the Pia Mater clothes them, and hides them with the infoldings of the Vessels; but this Membrane being pulled away, they are so conspicuous, especially in a Man and a Dog, that they seem like greater Nerves. In those Animals, where the annulary Protuberance is greater, these processes being brought from the same in right angles, are greater and more conspicuous; and on the contrary, in Fowl they are clearly wanting.

Concerning this hinder Region of the Head, there is not much besides worth noting, except the pro∣ductions of the Vessels. But there are Vessels which chiefly belong to these parts, the latter •…•…ix pair of Nerves arising within the Skull and the Vertebral Arteries. We have already described in some measure the beginnings of the former; what belongs to the more full knowledge of them, we shall leave to be handled in its proper place. As to the Vertebral Arteries, they reach from about the farthest end of the oblong Marrow, now about to end in the spinal, to its sides. These Vessels, as they are smaller, so they enter the Skull with lesser provision than the Carotides; for they are neither flourished first with Net∣like infoldings, nor are carried in a long journey by compassing about; but either Artery, passing direct∣ly through the Cuniform or Wedge like Bone, embraces the medullary Trunk on either side. Although these go •…•…orward divided for a little space, yet afterwards they are united, and with a single channel or passage, they meet with the posterior Carotides inclining mutually one towards the other; and so all the branches, meeting as it were in a threefold way, are inoculated one in another. The Vertebral Arteries, first shewing themselves within the Skull, are disposed otherwise in Brutes than in men: in the latter they fall through the sides of the oblong marrow parallel for some space, then as it were with a certain semi∣circular compass, they mutually incline one towards the other, and presently meet. The branches which first go forwards divided, are sometimes only two, to wit, one on either side, sometimes three, and then besides the two former, another is produced in the middle. But in Brutes, either Trunk of the Vertebral Artery, at the first coming to the Marrow, inclines presently to the meeting of the other with an acute angle, and quickly both meet together. The Vertebrals, even as the Carotides, send forth manifold branch∣es in their progress with an innumerable series of shoots, which cover over the oblong marrow, the Ce∣rebel, and all their cavities and recesses, and water them all with a plentiful flood of blood.

These are the Phaenomena or Appearances which the whole frame of the Brain and its Appendix is wont to exhibit to Anatomical Inspection, and which, as to its fabrick, and all its parts, and processes, are to be found both within and without. As it is a hard and troublesome business to inquire into the actions and use of each of these, so it is also joyned with so much pleasure and profit, that I dare promise to my self and others, that it will be a thing worth our labour and while. Yet before we enter upon this, there remain to be unfolded some things hid in some of the bones of the Skull, such as are the pituitary Kernels, the admirable Net, and some others; also we ought to shew first, briefly at least, a type or figure of the Brains in Fowl and Fishes.

[illustration]

Fig III

CC p. 57.

[illustration]

Fig. IIII.

DD p. 57.

The Third Figure.

SHews the outmost or superiour superficies of the humane Brain taken out of the Skull; where the border of the Brain being loosned from the knitting of the other Parts, made by the Membranes, is elevated and turned out∣ward, that the shanks of the oblong Marrow, the Fornix or arched Vault, the Nates and Testes, with the pineal Kernel, and other, Processes, may be clearly and distinctly beheld.

• AA. The border of the Brain, which in its natural fituation was contiguous to the Cerebel.
• B. The brim or margent of the callous Body besmearing either Hemisphere of the Brain, which in its natural site leans upon the pineal Glandula.
• C. The Fornix or arched Chamber.
• DD. The Arms of it embracing the shanks of the oblong Marrow.
• EE. The shanks of the oblong Marrow, out of which the Optick Nerves proceed, and the tops of which (situa∣ted further out of sight) are the streaked Bodies.
• F. The pineal Glandula, between which and the root of the Fornix, stands the chink leading to the Tunnel.
• GG. The orbicular Protuberances which are called Nates or the Buttocks.
• HH. The lesser Protuberances called Testes or the Testicles, which are Excrescencies of the former.
• II. The medullary Processes which ascend obliquely from the Testes into the Cerebel, and constitute part of ei∣ther of its Meditullium or marrowy part of it.
• K. The meeting of those Processes through another transverse or cross Process.
• LL. The beginning of the pathetick Nerves out of the meeting of the aforesaid Processes.
• MM. A portion of the oblong Marrow lying under the aforesaid Processes and Protuberances.
• N. The hole of the Ventricle, or Cavity which is placed under the orbicular Protuberances.
• OO. A portion of the annulary Protuberance sent from the Cerebel, and embracing the oblong Marrow.
• PP. The outmost and upper superficies of the Cerebel.

The Fourth Figure.

The Effigies of an humane Brain of a certain Touch that was foolish from his birth, and of that sort which are commonly termed Changelings; the bulk of whose Brain as it was thinner and lesser than is usual, its border could be farther listed up and turned back, that all the more interior parts might be more deeply beheld together.

• AA. The border of the Brain lifted up, and very much bent back, which in its natural site, being knit to the ob∣long Marrow, nigh the Cerebel, did hide the Nates and Testes.
• B. The border or inferior margent of the callous Body.
• CC. The Fornix, with its two Arms, embracing the shanks of the oblong Marrow.
• DD. The internal cavity or hollowness of the Brain resulting from the folding together of its border about the oblong Marrow.
• EE. The tops of the shanks of the oblong Marrow, or the streaked or ehamfered Bodies.
• FF. The Chambers of the Optick Nerves.
• G. The pineal Kernel, between whiois and the root of the Fornix the hole is, whose passage leads both to the Tunnel, and to the Ventricle lying under the orbicular Protuberances.
• HH. The Protuberances called Nates.
• II. The Protuberances called Testes.
• KK. The medullary Processes stretching out from the Testes to the middle of the Cerebel.
• LL. The laid aside Hemispheres of the Cerebel cut in two through the midst, that the Trunk of the oblong Mar∣row may be the better seen, where its medullary substance branches out into the form of a tree.
• M. The Furrow below the medullary stock, which being covered by the Cerebel, makes the fourth Ventricle in the form of a writing pen.
• NN. The medullary Processes which seem to be passages out of the oblong Marrow into the orbicular Protube∣rances.
• O. The end of the oblong Marrow giving place to the spinal.

CHAP. IV. The Parts and some of the Contents of the separated Skull unfolded.

IT is not our intent, nor will it be necdful for us to delineate the figures and situation of the several Bones of the Brain-pan, or to describe their various holes, which transmit the Trunks of the Vessels like the hanging weights of a Clock. All these are well enough known; so that to treat of these Gates or Entties is superfluous. Besides also, by what means the Nerves, arising within the Skull with their ramification or branching forth, enters the dens and caverns of the Bones, shall be delivered particu∣larly afterwards. Wherefore for the present our business shall be only to take notice of some things, chiefly worth noting, concerning the sanguiferous Vessels passing through the Cuniform or Wedge-like Bone, not sufficiently noted by others.

Among the various uses and offices which the Cuniform or Wedge-like Bone yields to the Brain and its Appendix, it is not of the least note or moment, that it transmits the Carotidick Arteries, not with∣out a certain mechanical or artificial provision; and that in the middle way, by which they must pass, it contains the pituitary Kernel, and sometimes the wonderful Net. Each of these deserve consideration; the more, for that in divers Animals they are after a different manner; and because it is much contro∣verted among Physicians concerning their frame and use. But we will first speak of the pituitary Glandula, because this part, being placed higher, is observable to Anatomical Inspection before others.

The pituitary Glandula or snotty Kernel is hid within a proper Cell or stall, made hollow in the middle of the Wedge-like Bone, being shut up in the Chest sometimes more strictly, sometimes more loosly: For in a Dog, Cat, and some other Creatures, sticking to the Tunnel, it is pulled away toge∣ther with it when it is removed; and then its bulk consists of two Glandula's or Kernels distinct among themselves, and easily to be separated one from another. But in a Calf, Sheep, Hog, and many others, it is strictly included on every side, except where it admits the Tunnel, and clothed with the hard Me∣ninx or dura Mater, and with its coverings shut up between the cavity of the Bone. Besides, in these, its frame or substance seems but one and undivided, though, in truth, it is made up of a substance which is of a twofold nature or kind.

This Glandula is found in all perfect Creatures; for Man, all four-footed Beasts, yea Fowl or Fishes are provided or endued with it: from whence we may conclude it to have some necessary uses in the Brain. But as to its quantity or bigness, its proportion is various in divers Animals, according to the bigness of the head and body wherein it is; because in a Lamb it is greater than in a Man or Dog; also Its bulk in a Horse is lesser than in an Ox. But the reason of this difference seems to consist in this chiefly, for that the pituitary Glandula in some, respects the bulk of the brain only laid upon it, and in others both the brain and the Carotidick Arteries ascending near it; and so as it hath a respect to both these together or only to one, its substance or bulk is either greater or lesser. For truly in some Animals the Carotidick Arteries being dilated within the Skull, are presently divaricated into Net-like infoldings, and from those infoldings many shoots of the Vessels every where enter this Glan∣dula, and are interwoven into its substance. Further, because this infolding of the Vessels, called the wonderful Net, is found very large in some, and in others very small; therefore this Kernel, for as much as it admits from these, few branches, and from those far more, and in some other Animals scarce any shoots from the Arteries, answers to this divers distribution of the Vessels, with the va∣rious proportion of its bulk. Because it is observed in some Animals, as chiefly in a Man and a Horse, that this wonderful Net is wholly wanting; and whereas in such, either Artery is carried about by a long compass between the recesses of this bone; from its trunk in a man sometimes one or two shoots, sometimes none, are carried into the pituitary Kernel; also in an Horse fewer branches en∣ter into it, and so its bulk in these becomes lesser.

But in very many other Animals (especially those who have the wonderful Net) it may be proved, besides ocular inspection, also by this Experiment, that many sanguiferous Vessels enter this Glandula; for if an inky liquor be squirted into the Carotides with a Syringe, the exterior part of the Glandula, that is interwoven with the blood-carrying Vessels, will be very much dyed with a black co∣lour. Wherefore without doubt, it may be thought, that this Glandula doth receive into it self the hu∣mors, to wit, flowing into it from the Tunnel in all kind of living Creatures, and in some from the branches of the Carotides. Yet by which way these humors are carried away again, doth not so plainly appear; for we affirm, with the most Learned Schneider, that they do not at all fall down into the Palate through the holes of the under-lying bone. Yet in the mean time, we suppose those holes to be only made to procure lightness to the bone; because in those Animals, which have the greater pituitary Kernel, those holes in the bone are more and larger: further, I have often found Vessels or Chanels to be contained between those holes; and when I had injected Ink within

the great hole of the same bone in a Calf, the black liquor presently entred the lesser Vessels subject to the bone, and at last the Jugular Vein. And by this Experiment chiefly we conjecture concerning the office and duty of this Glandula; of which we shall speak more fully hereafter, when we inquire into the use of this and the Tunnel.

Nigh to either side of the pituitary Kernel, if the dura Mater be opened, the Carotidick Artery Iyes stretched out upon the wedge-like bone, about the length of an inch: for as this Artery rises up below the Turky-Chair, sometimes higher, sometimes farther within the Skull; the same being presently bent in from its first ascent, goes in under the dura Mater till it comes to the anterior bor∣der of the same Chair; where again being intorted, and being sent forth upwards with a certain compass, it perforates the hard Meninx, and is carried straight towards the Brain. So this Vessel with its double ascent and crookedness (to wit, above the Basis of the Skull, and then above the hard Meninx, together with its situation, stretcht out in length under the same) represents in most the letter 〈☐〉〈☐〉 inversed; but in a man (as shall hereafter be more largely shewn) its site, by reason of the longer tract of the Vessel and its greater curvature, represents the same letter double after this man∣ner 〈☐☐〉〈☐☐〉.

The Carotidick Artery in all Animals ascends obliquely within the Skull, but as to its site or protension nigh the pituitary Glandula, it is not after the same manner in all: for in a Man passing through the Canal-bone, peculiarly ingraven by it, with a single Trunk, it lyes every where stretched out at length; and out of this Trunk it sends forth sometimes, though not always, some shoots to the pituitary Glandula. Also in a Horse, its Trunk is single; but where it first arises within the Skull, either Carotides, through the cross branches sent from one side to the other, be∣fore they perforate the dura Mater, communicate among themselves. And as in most other living Creatures, the Artery, however before branched forth, yet being made one single Trunk, goes into the Brain; in a Horse either Carotick Artery being parted in two, sends forth upwards two branches, arising from the dura Mater, in two distinct places.

In a Dog, Fox, Sheep, Calf, Stag, and many other four-footed Beasts, either of the Carotides, whilst hid within the Skull under the dura Mater, being divided into small shoots, and complica∣ted with other Vessels, to wit, both Veins and nervous Fibres, constitutes the Net-like infoldings; which infoldings, being stretched out on either side of the Turky Chair, fill the cavity there exist∣ing; then after manifold divarications of all the Vessels, some arterious shoots being disintangled from the others, and again united, grow together into one Trunk, which boring thorow the dura Mater, passes straight into the Brain.

The aforesaid infolding is, commonly called the wonderful Net, and that deservedly, for there is no∣thing in the whole fabrick of the animal Body more worthy of admiration; in which, besides the ar∣terious little branches which proceed from either of the ascending Carotides, the veinous shoots, though fewer, meet with those descending from the inward Jugular branches; and both kinds of Vessels being divided into small shoots, like a bundle of twisted silk, are variously folded together; which complications of the Vessels however are sustained by the nervous Fibres, supplied from the greater Trunk of the fifth pair of Nerves. The aforesaid infolding of the Vessels or wonderful Net in some Animals is far greater, and contains much more divarications of the Vessels than it hath in others; for in a Calf, Sheep, Goat, which are fed with grass, its frame is larger than in a Dog, Cat, and other flesh-eating and hotter Brutes. Further, it is observable, where the wonderful Net is greater, that the infolding of one side is ingrafted into the infolding of the other opposite side, and that from both, many more shoots of the Vessels do enter into the pituitary Kernel; so indeed, that if you shall inject Ink into the Trunk of the Artery below the Skull, the Vessels on either side, or the infoldings, will be dyed with the same tincture, and the black liquor will flow out of the Trunk of the opposite Ar∣tery.

In truth we have often seen this kind of Experiment repeated. Let the Carotidick Arteries be laid bare on either side of the Cervix or the hinder part of the Head, so that their little Tubes or Pipes, about half an inch long, may be exhibited together to the sight; then let a dyed liquor, and contained in a large Squirt or Pipe, be injected upwards in the trunk of one side, after once or twice injecting, you shall see the tincture or dyed liquor to descend from the other side by the trunk of the opposite Artery: yea, if the same be more copiously injected towards the Head, from thence returning through the Artery of the opposite side, it will go thorow below the Praecordia, even to the lower Region of the Body; when in the mean time, little or nothing of the same tincture is carried thorow the outward and greater Jugular Veins. Then the Head being opened, all the Arteries, before the entrance of the Head, and the Veins of the same band with them, will be imbued with the colour of the same injected liquor. Further, in the Vessels which constitute the wonderful Net, and which cover the Basis of the Brain, some foot∣steps of the same tincture will appear. But that this liquor doth descend so plentifully by the opposite Artery, and not by the Jugular Vein, either associate or opposite, the reason is, because it cannot enter those Veins, unless the region of the whole Brain, being first passed thorow, it had entred the bosom; but the liquor being plentifully injected, could not so suddenly pass through the very small Vessels co∣v•…•…ring the Brain: wherefore rather than the force should be carried to the Brain by the violent impulse of the liquor, it returning from the injection, and otherwise threatning a flood to the Brain, finds the

way of receding also by the opposite Arteries, for that end, both before they enter the Brain, and after they have entred it, communicating among themselves. And here we cannot sufficiently admire so pro∣vident (and to be equalled by no mechanical Art) a dispensation of the blood within the confines of the Brain. For in as much as the Carotidick Arteries do communicate between themselves in various places, and are mutually ingrasted; from thence a double benefit results, though of a contrary effect: because by this one and the same means care is taken, both lest the brain should be defrauded of its due watring of the blood, and also lest it should be overwhelmed by the too impetuous flowing of the swelling stream or torrent. As to the first, lest that should happen, one of the Carotides perhaps being obstructed, the other might supply the provision of both; then, lest the blood rus•…•…ing with too full a torrent, should drown the chanels and little Ponds of the brain, the flood is chastifed or hindred by an opposite Emissa∣ry, as it were a Flood-gate, and so is commanded to return its flood, and haste backward by the same ways, and to run back with an ebbing Tide.

By this kind of provision the Arteries about to enter the Brain are provided: yea, and the passages of the Veins, destinated for the returning of the blood from thence, seem also to be disposed with a won∣derful artifice. For when the anterior bosoms transfer their load into the two Laterals, which are the posterior, and they themselves end in the Jugular Veins, it is observed, that those latter bosoms have furrows or cavities insculped whereby they may settle or rest upon the hinder part of the Head; and when as either bosom, through a proper hole, being about to go into the Jugular Vein, slides out of the Skull; nigh that hole, in the outward part of the Skull, a round and ample den is made hollow, and co∣vered over by the extremity on either side of the same bosom, inlarged into a greater capacity, to the end, that the blood, whilst it slides forth out of the Head with a full torrent, should not rush into the Veins with too rapid and vertiginous an influx, and so make a forcible entry on the Heart it self, therefore it hath here a diversion large enough, in which estuating or boiling up, till a more free and open space may be granted to its course, it may be staid without any trouble. Certainly there can be nothing more artificial thought upon, and that can better argue the Providence of the great Creator, than this fit or convenient disposition of the blood in the brain, and without it, and the way of its reciprocation in divers Animals, accommodated to the necessity of every one. And lastly, in the dissection of Beasts, other miracles of the same nature happen, whereby shewing the Finger and Divine Workmanship of the Deity, a most strong and invincible Argument may be opposed to the most perverse Atheist.

The Fifth Figure.

SHews the interior Basis of an humane Skull; where is shewn after what manner the Vessels of every kind cut off from the Brain, and about to go out of the Skull, are hid or laid up under the dura Mater.

• A. The hollowness of the Bone of the Forehead.
• B. The close or mound of the Cribriform or Sieve-like Bone.
• CC. The mammillary Processes, which are much thinner, and endued with a less open cavity, than in four∣footed Beasts, endued with a more excellent sense of smelling.
• DD. The Optick Nerves, being far separated, go out of the Skull otherwise than in most brute Beasts.
• E. The pituitary Glandula or Kernel with the top of the Tunnel inserted into it.
• FF. The Carotidick Arteries shewing themselves nigh its sides.
• GG. Tqe moving Nerves of the Eyes going out of the Skull.
• HH. The pathetick Nerves, hid under the dura Mater, go out from the Skull at the same hole with the former.
• II. The fifth pair of Nerves hid under the dura Mater.
• KK. The sixth pair stretched forth under the dura Mater, and go out also at the same hole with the third and fourth pair.
• LL. The seventh pair entring with a double Process the stony Bone.
• MM. The eighth or the wandring pair seen to grow together with an accessory Nerve of many Fibres, NN. as it goes out of the Skull.
• NN. The accessory Nerve to the wandring pair.
• OO. The ninth pair.
• PP. The tenth pair tending downwards, hid under the dura Mater, where the Vertebral Artery ascends,
• QQ. The lateral or Side-bosom.

[illustration]

Fig. V.

EE. p. 60

[illustration]

Fig. VI.

FF. p. 61.

The Sixth Figure.

SHews the Basis of a Calfs Skull; where is shewn after what manner the Vessels cut off from the Brain, and about to go out from the Skull, are drowned under the dura Mater.

• AA. The hollownesses of the spongie Bone.
• BB. The mammillary Processes, which, the smelling Nerves being cut off, appear hollow.
• C. The Optick Nerves united, being presently separated again, they go out of the Skull.
• D. The pituitary Kernel.
• EE. The Carotidick Arteries emerging nigh its sides.
• FF. The motory Nerves of the Eyes going out of the Skull.
• GG. The pathetick Nerves of the Eyes, hid under the dura Mater, going out of the Skull at the same hole with the former.
• HH. The fifth pair of Nerves demersed under the dura Mater.
• II. The sixth pair drowned under the dura Mater, and going out at the same hole with the Fourth and Fifth.
• KK. kk. The seventh pair entring the stony Bone with a double Process.
• LL. The eighth pair, or the wandring pair, with many Fibres, and an accessory Nerve, seen to grow together, going out of the Skull.
• MM. The ninth pair.
• NN. The tenth pair tending downwards, hid under the dura Mater.

CHAP. V. The Brains of Fowls and Fishes described.

WHat hitherto we have shewn concerning the description of the Brain and its Appendix, we chiefly owe to the observations made of the dissection of the Heads of a Man and of four∣footed Beasts. We shall now proceed to the commenting upon these Observations; to wit, that we may endeavour, from the fabrick rightly considered of the parts of the Brain, so de∣scribed, to erect their offices and uses, and so to design the government of the animal Function: But because a compared Anatomy may yield us a more full and exact Physiology of the Use of Parts▪ there∣fore before I enter upon this task, it will seem worth our labour to inquire into the Heads of some other Animals, to wit of Fowls and Fishes.

We have already hinted, that the Brains of Men and of four-footed Beasts, were alike in most things; and also that the contents in the Heads of Fowls and Fishes being far different from both the former, yet as to the chief parts of the Head, are found to have between themselves an agreement. The kinds of ei∣ther Animals being coetaneous, and as it were Twins from the Creation of the World, do testifie their affinity in nothing more than in the fabrick of the Brain. That it is so in Man and four-footed Beasts plainly appears already: we shall now see if that the Anatomy of Fowls and Fishes will shew us any thing worthy of note.

That we may begin with Fowls; the covering of the Skull being taken off, the hard Meninx or Mem∣brane embraces strictly the bulk or mole contained within. In the midst of it, where the brain is divi∣ded into two Hemispheres, it hath a bosom stretched out at length, which notwithstanding, no Falx (or Scythe) being let down between the interstices, is inserted less deeply in the brain; then, where this Mem∣brane distinguishes between the Brain and Cerebel, two lateral bosoms are formed. Besides in Fowls there is a fourth bosom, which hath its place a little more backward than in men or four-footed beasts; for a little below the pineal Kernel a hollow and smooth process of the hard Meninx is sent down •…•…pon the stranks of the oblong marrow, where presently it is divided into two branches, on either side whereof it it sends forth one upwards into the cavity between the streaked Membrane and the Hemisphere of the brain, planted in the hinder part of the brain.

This superior Membrane or hard Meninx being cut off, and separated round about the Pia Mater, appears very thin, which is not, as in man or other perfect Creatures, marked with such frequent infoldings of the Vessels; but this most subtil Meninx being made of a texture of Fibres, only clothes, and every where inti∣mately binds about the even and plain superficies of the brain contained within, and wholly destitute of turnings and windings about.

The fabrick of the brain in Fowls is otherwise than in man or four-footed beasts: for besides that in its compass the inequalities and the turnings and windings are wholly wanting; also more inwardly, the callous body and the Fornix, as also the chamfered bodies, which we described before, are all lacking: and besides, the substance of the Brain it self is figured after another manner. That these may the better

be beheld, make the dissection of the Brain of a Goose or a Turky-Cock; and the Membranes being cut off, by pressing lightly the fissure or cleft of the Brain, you may divide the middle of it one from ano∣ther, and go forward to separate it, till you come to its bosom, in which place are two marrowy bo∣dies, which being stretched out like Nerves, connect the Hemispheres one to another. Either side of the In∣terstitium or the space between, is clothed with a whitish Membrane, which is marked with streaks or beams, lying or running from the whole compass or circumference, to the lower corner; and these streaks concenter about the insertions of the medullary bodies. Then, if this Membrane be cut, in ei∣ther Hemisphere of the Brain there will appear underneath a cavity, which goes under the whole space, from the side of the Interstitium, and for a great part, the hinder region of the Brain, and is arched or chambered with that streaked Membrane. Either cavity or hollowness, about the bottom, is opened in∣to an intermediate or common pafsage, which lies open to the Tunnel; and from either side of this passage the shanks of the oblong Marrow are stretched out, to which, on either side, the Hemisphere of the Brain is hung by two medullary bodies; to wit, one marrowy or medullary body goes out from the mole or substance of the Brain lying under the Ventricle, the other from the streaked Membrane covering the Ventricle. From these two, placed on either side, the medullary bodies being stretched out cross∣wise, like Nerves, joyn the two Hemispheres of the Brain to one another. Besides, these two growing together on either side, fix either Hemisphere of the brain to the shanks of the oblong marrow.

So the Figure of the Brain in Fowl, if you compare it with the Brain in men and of the more perfect four-footed Beasts, seems to be as it were inversed. For as in these the Cortical part is outward, and the medullary laid under it; so in Fowls, the lower frame of the Brain, which consists of a thick and closer substance, is instead of the Cortex or Shell; but the outmost and upper Membrane, chambering the Ventricle, appears medullar or marrowy above any other part. Moreover, the Ventricles in the Brains of a Man and four-footed Beasts are beneath, and near the bottom; in Fowls, above and nigh the out∣ward border. The reason of this difference seems to be, because placed in a more perfect brain, such as is in Man and four-footed Beasts, the animal Spirits have both their birth and exercise; viz. they are procrea∣ted in its Cortical or shelly part, and in its medullary, which being large enough, lyes under this, they are circulated and variously expanded for the acting of their faculties. But truly in the Brain of Fowls there is space enough for the generation of Spirit, but for their circulation there is scarce any lest: to wit, the Brains of Birds seem not to be much possessed with the gifts of phantasie or memory: yet it is thought, that the Spirits begotten in the Brain are exercised chiefly in the oblong Marrow for the preserving the animal function; for there, as we shall shew anon, the medullary substance, which is instead of the cal∣lous body, consists; and like the streaked bodies in others, in these are streaked Membranes, through which the Spirits, procreated in the Brain are carried, without any order there, forthwith into the ob∣long Marrow: but because the Spirits, begot in the brain, ought to lay aside a serous excrement; therefore the Ventricles from the complicature of the streaked Membrane upon the keel or lower part of the brain, and on the oblong Marrow it self, do serve conveniently enough for this business. Notwithstanding, be∣cause in the Brains of Fowls, the Fornix is wholly wanting, there are only two anterior Ventricles; be∣tween which, the Choroeides infolding is stretched out; the veinous portion whereof, as was but now said, arises a little lower from the fourth bosom; but the Arteries ascending, come from either side of the oblong marrow.

Nor is there a greater heterogeneity or difference of conformation in the Brain it self of Fowls, than in the oblong Marrow from the same in men and four-footed Beasts. For in the first Section, from whence the Optick Nerves arise, two noted protuberances grow to either side. These are much greater in proportion than the orbicular prominences in the more perfect Creatures; so that they seem another additional Brain: either of them of a white colour, and purely marrowy, is hollow within; so that in these kind of Animals are found two Bellies or Ventricles in the Brain, and as many in the oblong Mar∣row. And seeing in these, as in all other Animals, a cavity is put under the Cerebel, the Ventricles in the whole Head differ as well in number as in figure and position.

In the middle of the medullary Trunk, to wit, where those prominences grow to its sides, the Chink, leading to the Tunnel is cut, but into it the aperture of either Ventricle gapes or opens, that it is not to be doubted, but that the serosities heaped up there, are sent out by that way. Moreover it is likely, that these hollow and medullary prominences in Fowls supply the course of the callous body, to wit, in which the animal Spirits are circulated for the exercising their Faculties: because in the Brain the space is so narrow, that the Spirits cannot be produced and circulated together within its confines. Further, as in Fowls, the use of the animal Spirits is required for the act of the sensitive and loco-motive faculty, more than for phantasie or memory; certainly the chief place where they may meet and be exercised, ought to be placed rather in the oblong Marrow than in the Brain.

The Carotidick Arteries, which carry the blood to the brains of the greater Birds, are so small, that there is no proportion of these to the same in man and four-footed beasts. Their Trunks being carried within the Skull, ascend without any branchings into net-like infoldings, after the same manner as in other Animals, nigh to the pituitary Glandula, and pass right into the brain, and distribute some small shoots of the Vessles both to its exterior compass, and through its inward recesses. But in truth, the brains of Birds are watered with a very small portion of blood, in respect of other living Creatures; be∣cause, where the fancy or imagination is little exercised, there is not much blood required for the refresh∣ing the animal Spirits.

Fowl (otherwise than some affirm) have both the mammillary processes, and the Cribrous or Sieve∣like bone. For the anterior productions of the brain being highly extenuated and involved with the Dura Mater, stretching out almost to the middle part of the bill, are inserted into the triangular bone, which hath a double bosom, distinguished between with a thin mound or pale. But these processes be∣ing dilated within the bosom of the aforesaid bone, and in Bladders full of clear water, which are very like the mammillary processes in a Calf, full of clear water. Besides, as out of the fifth pair of Nerves a noted branch on either side passing through the ball of the Eye, enters into the cavern of the Nostril, a shoot of it being sent out of the Trunk, is bestowed to the very Orifice of the Nostrils; in the mean time, both the greater Trunks, compassing about the Cribrous bone, meet together, and presently going one from the other, and being carried to the end of the bill, are distributed into the palate. After this man∣ner Fowls, even as men and four-footed beasts, are furnished with a peculiar organ of smelling, to wit, with a double mammillary process; and besides, they have within the Nostrils additional Nerves out of the fifth pair, by whose action and communication of branches into other parts, and among themselves, so strict an affinity is contracted between the smell and the taste. The other pairs of Nerves are almost after the same manner as in men and four-footed beasts. In like manner we also observe, that there is no great difference as to the Cerebel and the other portion of the oblong marrow; between Birds and the other Animals we have already considered on, unless that the orbicular prominences before the Cerebel, and the other annulary under it, meeting within them, are both wanting in Fowls; indeed these latter seem not at all to be required; but instead of the former, they are easily supplied from the hollow me∣dullary prominences, such as we have shewn to be in Fowls.

And these are what are chiefly worth noting to be found in the brains of Fowls. We have already men∣tioned, that there is a certain likeness between these and Fishes as to the most parts of the head; wherefore it will seem to be to the purpose, that here for a conclusion we should say something of the brain of Fishes. First, we shall observe, that as the heads of Fishes, in respect of the whole body, are greater than of any other living Creatures, yet they contain in them less brain than others. For two little moles or substances, placed before, sustain the whole place of the brain, properly so called; out of these, two signal smelling Nerves proceed; which are carried by a long and straight journey to the holes made hol∣low, out of either side of the mouth, and which are instead of nostrils: and this is singular to Fishes. Moreover, we advertise concerning the Optick Nerves, that they, as in other living Creatures, inclining mutually one to the other, are not however united, unless perhaps towards the superficies; but they are crossed, and a Nerve arising from the right side of the oblong marrow, is carried into the left Eye, and so on the contrary: so indeed, that the visory rays have their refraction, not only in the Eye, but within the very bodies of the Nerves. The oblong marrow in Fishes, wholly after the like manner as in Birds, hath two signal protuberances hollowed withi•…•… and in truth, as to local motions, the Spirits in either seem to be exercised after the like mode. For as Fishes swim in the water, so the flying of Fowls or Birds seems a certain kind of swimming in the Air. Further, in these 'tis observable, there are the pi∣tuitary Kernel, the Tunnel, and the Carotidick Arteries as in other Animals; also many pairs of the Nerves have the same origines and distributions, excepting that the hearing Nerves are here wanting; although Casserns Placentinus attributes this gift to the smelling Nerves. The figure of the Cerebel is the same as in more per•…•…ect Animals. Besides, what we have remarked concerning the wandring pair of Nerves in man and four-footed beasts; to wit, many fibres of it arising together, the trunk of the Nerve from the spinal marrow comes to them: in like manner the same is in Fishes. But to describe them all further is needless, for the rest, as those which are proper to them only and Birds, as also those which they have common with Fowls and the more perfect Animals, may be easily known, partly out of the peculiar similitude with birds, and partly out of the universal Analogy of all. Therefore we will now philosophise upon the Use and Action of the Brain and its Parts, and of its Appendix, together with the whole oeconomy of the animal Function: where in the first place, we will inquire into the offices of a more perfect Brain, such as of man and four-footed beasts; and also secondarily and collaterally we shall explain the Offices and Actions of a less perfect Brain, and of its Parts, such as that of Fowls and Fishes.

CHAP. VI. Of the Offices of the Brain and its Parts: where first of all the Uses of the Skull and the hard Meninx or Dura Mater is treated of.

THE Poets seigned Pallas to be formed within the Brain of Jupiter, and from thence to be born. In truth, within the Womb of the Brain all the Conceptions, Ideas, Forces, and Powerrs whatsoever both of the Rational and Sensitive Soul are framed; and having there gotten a species and form, are produced into act. Wherefore it will be worth our labour to inquire into these places, of the generation of these more noble faculties, and the first rise and primitive beginnings of them, as also more curiously to consider the divers parts of the Brain, or the Organs ser∣ving to their Generation: And I go about this part of my labour the more willingly, that I may by handling the thread of our dissection again, bring all the Phaenomena, before given to our inspection and sense, before the Eye of Reason, and to be again weighed by a more severe Examination of Discourse; at least those things which seem to be of the greater moment, and chiefly worth taking notice of. Neither do we think here to heap up into a great Volume the several things worn out by the handling of others, and offered to common observation.

Therefore recollecting the Anatomy of the Brain, the first things to be considered are its coverings, to wit, the Skull, and the two Meninxes or Maters. Concerning the first it is observed, that all perfect Ani∣mals have an hard and bony Skull. A double reason for which may be given: First, that the Head being destinated for the most noble use, might be protected with a more firm and not easily penetrable cover∣ing, as a natural Helmet, against the injuries of external strokes; besides secondly, as this is in the place of Armor, so also of a Cloister; because the same covering the dura Mater within, may restrain and keep within the Brain the Effluvia's of the animal Spirits, lest they should too thickly evaporate, or in heaps. Further, as the Skull for these ends is made bony, the efficient cause are the saline Particles of the blood watering the brain, which being unprofitable to the interior work of the animal Spirits, and so to be sent away outwardly, grow together thus in the circumference, and are congealed into a stony hardness: For indeed the blood being carried towards the Head, as it abounds very much in Spirit, so in Salt; its Particles highly volatile, being joyned to the Spirits, are bestowed on the brain; in the mean time, the saline little bodies, which are of a more fixed nature, being thrust out into the circumference, from the Spirit implanted in the Brain, constitute the stony Skull, as it were a bubble covering inclosed wind.

Within the hollow superficies of the Skull, there appear many furrows and inequalities imprinted by the proturberances of the Vessels; and we perceive frequently either border or plate of it to be perforated by the passing through of the Vessels in several places: but the Arteries, arising in the exterior superficies of the dura Mater, make these kind of little ditches through the concavity of the Skull. For when the whole substance of the brain is at first soft, and easily giving place, like Wax; the Arteries underneath it continually beating, as it hardens by degrees, easily imprint the marks of their tracts.

The figure of the Skull in four-footed beasts is narrow and prest down, but in man, the substance of whose brain is large, there is required a more capacious and almost spherical figure. For as God gave him an upright countenance to behold the Heavens, and also endued his brain with an immortal Soul, and fitted for the speculation of Heaven; therefore his face is erect or lifted up; so the brain it self is placed in a more eminent place, to wit, above the Cerebel and all the Sensories. But in Brutes, and such whose faces are prone towards the Earth, and have a brain unfit for speculation, the Cerebel, however ser∣ving to the more noted action and office of the Praecordia, is placed in the highest seat to which the mole of the brain is subjected. Besides, some organs of the Senses, to wit, the Ears and Eyes, if they be not superior, they are placed at least equal to the brain. In an humane Head, the Basis of the Brain and Cere∣bel being placed nigh together, yea of the whole Skull, is made parallel to the Horizon; whereby it comes to pass, that there is less danger for any portion of the head to be jogged here and there, or to be moved out of its proper seat; But in four-footed beasts, who go with an hanging down head, the Basis of the Skull makes a right angle with the Horizon; wherefore the brain being subjected, the Cerebel is put in the highest place; so indeed, that this seems less stable, and that it may shake, or be moved from its seat. However against this inconvenience, lest a frequent concussion of the Cerebel might induce a sink∣ing down or loss of the Spirits, or irregularities about the Praecordia, in some it is taken care of by a won∣derful artifice of Nature; for as in all the frame or substance of the Cerebel is most strictly bound fa•…•…t together by the Dura Mater, besides in some it is staid by a bony fence; but in others, as in a Hare, Rab∣bet, and other lesser Brutes, a certain portion of the Cerebel is included on either side by a stony bone, and so by this double hold its whole bulk or substance is firmly tyed to the Skull. Concerning the chief bones of the Skull, viz. the Cuniform or Wedge-like bone, the Cribrous or Sieve-like bone, and the auditory or hearing Organ, they shall be spoken of in their proper places, when we come to treat particularly of the

Ventricles of the Brain, and of the Senses to which these bones serve. We shall pass next to the hard Meninx or dura Mater.

The dura Mater or hard Meninx, formed of a double kind of Vessels and Processes, bears also a double Aspect, and ows part of its office to the Skull, that is about it, and part to the Encephalon contained within it. The exterior processes of this Membrane are insinuated within all the bosoms and cavities of the Skull; to some whereof they are a covering and defence, but to others they impart a sensible force, which manifestly appears in the Sieve-like bone, through whose holes the fringes of this Membrane pas∣sing, conduce something to the sense of smelling. Also the productions of this, lying over the recesses and caverns of the Wedge-like bone, fortifie the ways for the entrance and coming out of the Vessels. The in∣terior processes of the dura Mater, which belong to the Head, divide and distinguish between the parts of the Brain and Cerebel; and in those places the dura Mater is very thick, lest in any great concussion of the Head, these two should be smitten one against another, and should press one upon the other. Where∣fore in Dogs (as we have already hinted) who are wont to run violently with their heads down, there is sent down between these bodies a bony fence. In like manner in a Cat, Horse, Fox, and many other Animals, from whose manner of living and use it is required, that they be moved with a swift motion, that bony fence, commonly called the Triangular Bone, is sent down deeply between the Brain and the Cerebel; yea, and all the bosoms pass through that bone in the holes curiously made hollow in it.

The Vessels belonging to the dura Mater are either Arteries, that carry the blood thither; or they are Veins, which receiving from thence the superf•…•…uous blood, and from the whole Head besides, return it towards the Heart. As to the first sort of Vessels, on either side, two Arteries arising from the Carotidick Artery on the same side, before it comes to the Basis of the Brain, are carried into the dura Mater: which notwithstanding, only possessing the exterior superficies or convex part, carry blood and juyce to this Membrane, also in some measure to the Skull and its coverings. As to the Vessels carrying the blood back, this Meninx contains four, into which, as into a great Sea, all the Rivulets of the Arteries, serving the whole Head, do exonerate themselves: to wit, there are observed in this Membrane four no∣ted Cavities, commonly called Bosoms; which are disposed after that manner, that, like Promptuaries or Store-houses framed in several places, they receive the blood returning from every region and corner of the brain: For the third bosom, or the longitudinal, looks towards the anterior brain, the fourth towards its middle; but the first and second admit the blood flowing back from the Cerebel and hinder part of the brain. Further, out of these the third and fourth disburden themselves into the first and second, and these at length transfer their burden into the Jugular Veins. On every side, from these bosoms, the lesser Vessels, viz. the chanels of the Veins are sent forth, which going out migh the interior or concave super∣ficies of the dura Mater, are presently inserted into the Pia Mater; and following its protension, being di∣stributed through the whole compass, and all the interior recesses of the brain and its Appendix within the Skull, and being complicated with the Arteries, receive the superfluous blood, and carry it into those greater cavities. That it is so, it plainly appears, because if you squirt a liquor, dyed with Ink, into the Pipe of the Artery, that passing through the arterious shoots, and then the veinous, goes through at last into the bosoms.

Whilst the blood, returning from the whole interior Head, is collected within those bosoms, as with a full belly, it seems also in another respect to be of a very notable use; to wit, for the supplying of heat, requisite for the distilling forth of the animal Spirits, as if it were a certain Chymical operation. For as much as the blood to be distilled, is contained in the Vessels, interwoven into the Pia Mater, the supe∣riour Rivers diffused on every side through the dura Mater, the heat being brought to it like a Balneum Mariae, flow about the under-lying blood, and so force out of it a most subtil Liquor into the substance of the Brain; or rather, the blood raising up heat within the bosoms, is like the fire of suppression, which in the distillation by descent, is inkindled round about the Vessel containing the matter to be distilled. For indeed the interior substance of the Brain, for that it is endued with plenty of Salt and very little Sulphur, is of a more frigid temper: wherefore, that from the blood watering its superficies, the spiritu∣ous part may be stilled forth, and forced into its middle or marrow, the degree of the ambient heat ought to be made the more strong, such indeed, as the blood collected in the ample Estuaries of the bosoms, may easily afford. Further, as those bosoms being distended with heated blood, are like a certain distilla∣tory Bath; so the other Membrane of the dura Mater being stretched out about the whole Head, is like an impervious Alembick, which with its covering keeps within the spirituous breaths, that they may not be immoderately evaporated.

Concerning this Membrane there may yet be considered, with what motion or sense it is endued. And as to sense, 'tis not to be doubted, but that it hath it exquisitely: For since all the Membranes have feeling, and owe that faculty to the afflux of the animal Spirits from the Brain, surely this Meninx, for that it is nearer and very much of kin to the Brain and its Appendix, so that it clothes very many Nerves going out of the Skull, it obtains a very accurate virtue of feeling: which thing also may be argued from the effect; because the pains of the Head often proceed from the breach of unity excited in this Membrane. But that it hath motion, it can hardly be thought, because it is tyed in very many places to the Skull; and yet it is probable, that the same may sometimes, in some parts at least, be contracted and wrinkled or drawn together: And certainly there is no doubt, that it is contracted and remitted in sneesing.

In like manner, when from an hurt of this a Vomiting or Convulsive motions follow in the Viscera or Members, this Membrane is the cause, which being somewhere contracted or divided, infolds with it self the substance contained within the same Convulsion or Spasm.

Concerning the motion of this Membrane, a curious mind may yet further consider its texture, and especially how it is within the cavities of the bosoms, and the Interstitium or separation of the Brain and Cerebel. For in these places are found many Fibres, or as it were greater or nervous cords or strings, such as we have observed to be variously stretched out in the Ventricles of the Heart. Within the bosoms, from the various processes of the Membrane, a cavity full of turnings and windings, and manifoldly di∣vided, as it were with many little Cells, is constituted. This seems to be thus made, to this end, to wit, that the blood returning back from divers little rivers into the cavities of the bosoms, may be retar∣ded by several obstacles, as it were little flood-gates; left perhaps rushing too impetuously and by heaps, it might flow within this Sea with a vertiginous and inordinate motion. But there is observed, besides these intrications and little cells of this Meninx in the heads of four-footed beasts, that moreover in the whole cavity of the bosoms, very many cords, as it were Ligaments, are every where produced from one side to the other. The office of these is partly, that they may contain the sides of the cavity within their due ends of aperture and dilation, lest they should be distended above measure by the vehement rushing in of the blood, and so may press upon the substance of the brain. Yea the contexture of these whitish Fibres, which are met with, both within the cavities of the bosoms, and in this Meninx, going about the Cerebel, and distinguishing between it and the Brain, seems to intimate, that they serve also to some motion. For it may be suspected, that those strong Fibres, and as it were Ligaments, do sometimes contract, sometimes dilate, and variously draw the Membrane to which they are knit. From these kind of motions of the dura Mater, the blood flowing within the bosoms, may be variously agitated, and as occasion serves, sometimes hastened in its Circle, and sometimes restrained or hindred; for in many affections of the sensitive Soul, the blood being disturbed from its equal circulation, is sometimes preci∣pitated by heaps and impetuously to the Heart, and sometimes detained from its nest longer, nigh the confines of the Brain. But that various whirl-winds of passions stir up such irregularities in the motion of the blood, the nervous parts implanted about the Praecordia, are in some measure the cause, which by contracting or dilating the same, variously moderate the course of the blood, yet so, that in the mean time, some part of this office is due from the brain it self, or at least to its Appendix. Indeed the brain it self wants motion; but the blood passing through its substance, for as much as it is poured wholly in this Meninx, and passes through its receptacles, is at the motion and beck of this Membrane, sometimes driven away from the brain, and commanded to succour the Heart, as in fear and great sadness, sometimes being hastened towards the brain, is for some time prohibited from flowing back, as in shame, indigna∣tion, and some other affections.

Truly, that these kind of interior processes of the bosoms, and as it were transverse strings or cords, do conduce to the more commodious reduction of the blood, we gather also from hence, that in work∣ing beasts, whose brain (because they feed and go with a prone and hanging down head) is in greater danger of an inundation of the blood, those processes are very big, for that they being successively con∣tracted, may leisurely thrust out the blood, apt otherwise to stagnate by reason of the inclination of the head. Neither is it from the purpose to observe here, that these same Animals are always furnished, for that reason, with a greater wonderful Net: by which means indeed it is provided, that the blood may not too much invade the brain by heaps; as care is taken by the artifice but now described, lest the same should make too long stay in the brain, and so oppress its more weak frame.

Therefore in the last place, that I may recollect what I have said of the dura Mater, and rehearse its chief uses: First, It covers over the Skull within, and reaches to it somewhat of nourishment by the Vessels. Secondly, It is a covering to the whole head, and serves to distinguish its chief parts. Thirdly, It con∣tains the Vessels designed for the reducing the blood from the whole interior head; which, in the mean time, by reason of the plenty of the blood contained in them, and the opportunity of their situation, ad∣minister requisite heat for the distillation of the Spirits. Fourthly, It provides ways for the admission and going out of all the Vessels within the Skull, and fortifies them; to which may be added, that it bestows on some of them their Coats; as shall be shewn anon. Fifthly and lastly, This Meninx being here and there contracted or divided by the animal Spirits variously moved, according to the passions of the Soul, or the necessities of Nature, stays the blood sometimes longer near the confines of the Brain, sometimes drives it forward from thence towards the Praecordia.

CHAP. VII. Of the thinner Meninx or Pia Mater, of its stretching out, as also of the Infoldings of the Vessels every where interwoven with it.

THE interior Meninx or Pia Mater is far thinner than the exte•…•…ior, and consists of a most sub•…•…le contexture of Fibres. This does not compass about the Encephalon's superficies as loosly as the Dura Mater; but embraces it so very strictly, that it is very hardly separated from it: besides, it insinuates it self into all its turnings and windings and furrows, and clothes their inward parts. Further, this Meninx, although it be thin, yet being covered over throughout with the infoldings of Arteries and Veins, is interwoven with them, and so waters all the spaces of the Brain and Cerebel with innumerable rivers. For as the Region of either of these, especially of the Brain, is full of turnings and windings, this Membrane in like manner grows to the deep furrows of the crankling turnings about, and also to the tops of the ridges; yea, the chief complications of the Vessels are still placed in the vallies, as if they were there hid in regard of their safety. Neither doth this Meninx only cover the gapings of the turnings and windings about; but also gathers together the tops or heights of all their interstices or places between, and knits them together, and so makes the whole superficies of the Head plain, globous, and as it were like the World.

That the diffusion of this wonderful Membrane into all the turnings and windings of the Brain, and the distribution of the Vessels through those most intimate recesses, may be the better beheld; let the head of a man, or of a brute beast that dyed of the Dropsie, be opened: For in such, whose brain abounds with much moisture, the little stays, whereby this Meninx is fixed to the substance of the brain, are loos∣ned, so that the Membrane, with the infoldings of the Vessels, may be easily drawn away, and pulled off almost whole: which indeed being pulled off, the folds of the brain will appear naked: also the inser∣tions of the Vessels every where into the more inward substance of the brain, may be perceived. But to a sound and dry brain the Pia Mater sticks so closely, that it can scarce be drawn away in any part, or se∣parated with a Penknife.

We have already shewn after what manner the Veins and Arteries (which creeping like Ivy, are knit into the Pia Mater, and variously interwoven into it) cover over with most thick little shoots, the whole compass of the Brain and Cerebel, and their Interstices, the gapings of the crankling turnings and wind∣ings about, bosoms and cavities, and send forth every where small shoots into the medullary substance; so that it is not to be doubted, but that the animal Spirits, being as it were stilled forth immediately from the blood, every where in the whole head, are received into the Pores and passages of the Brain and Ce∣rebel. From whence it will be easie to assign the use or office of the Pia Mater, viz. First, this Membrane clothes the universal parts of the whole Encephalon, and distinguishes them all one from another. For in∣deed, this lying over all the gapings and interstices of the turnings and windings, is instead of a mound or sence, by which the animal Spirits are restrained every where within their proper cells and orbs of expansion, nor are they permitted by this means to run beyond their bounds, and so confound the acts of the many Faculties. Then secondly, this Meninx sustains all the blood carrying Vessels, viz. both the Arteries and Veins, together with their manifold productions, and so affords a passage to the blood, by carrying it to and fro towards the brain.

Concerning these Vessels, which are knit to this Meninx, and follow its stretching out into all parts, there are many admirable things to be met with, and highly worthy of note, the uses and reasons of which is our purpose to search into.

As to these, we shall first observe, that these Arteries and Veins, otherwise than in any •…•…ther part of the body besides, not arising nigh one another, go forth as companions, but going forth from opposite ends, meet every where mutually, viz. the Arteries ascend from the Basis of the Skull, and by creeping through the whole, emit upwards shoots and branches, which are met by the Pipes of the Veins arising out of the bosoms, and carried downwards. By this means the rivers of the blood seem to be made equal eve∣ry where in the Brain, viz. whilst the smaller shoots of the Veins follow or match the greater branches of the Arteries, and on the contrary, the small branches of the Arteries the Trunks of the Veins.

Secondly, We have already shewn, that these Vessels are variously and very much ingrasted or inocula∣ted among themselves, not only the Arteries with the Veins, but what is more rare and singular, Arteries with Arteries; to wit, the Carotidick Arteries of one side, in many places, are united with the Carotides of the other side; besides the Vertebrals of either side among themselves, and are also inoculated into the posterior branches of the Carotides before united. The joynings together of the Carotides, in most living Creatures, are made about the •…•…asis of the Skull under the Dura Mater, and that after a diverse manner, in some communicated through the Vessels of the Wonderful Net from one side to the other; in others (as in a Horse we have observed with a certain admiration) the arterious chanel is

produced between the Trunks of the Carotides, whereby the blood may be carried from one side to the other, and so on the contrary. But besides, between the Dura Mater, about the Basis of the Head, the same kind of ingraftings of the Arteries are still seen in man and all perfect four-footed beasts.

The reason of these seems to be partly, that the blood to be carried from the Heart into divers Regions of the Brain, might be exactly mingled as to its parts and particles, before it come to the place designed. For the Torrent of the blood, because divided into lesser rivulets, is incident to languish in so long a cir∣cuit, and its Spirits to be depauperated, and lastly it self to grow cool, unless that various courses of its Latex should anew inkindle this vital flame about to be extinguished or dye.

But there is another reason far greater than this of these manifold ingraftings of the Vessels, to wit, that there may be a manifold way, and that more certain, for the blood about to go into divers Regions of the Brain, laid open for each; so that if by chance one or two should be stopt, there might easily be found another passage instead of them: as for example, if the Carotides of one side should be obstructed, then the Vessels of the other side might provide for either Province. Also as to the Vertebral Art•…•…ies, there is the same manner of provision made. Further, if both the Carotides should be stopped, the o•…•…ces of each might be supplied through the Vertebrals, and so on the other side the Carotides may supply the defects of the shut up Vertebrals.

After this manner, lest there should be wanting an afflux of the blood at any time in any part of the Brain, or its Appendix, within the Skull, there is care taken with singular Art: For as there are four di∣stinct passages, and those remote one from the other, of this Latex, if perchance three of them should happen to be shut up, the blood being carried through one only, will soon supply or fill the chanels and passages of all the rest. Which thing I have found by experience often tryed, not without admiration and great pleasure. To wit, I have squirted oftentimes into either Artery of the Carotides, a liquor dyed with Ink, and presently the branches on either side, yea and the chief shoots of the Vertebrals, have been dyed with the same tincture: yea, if such an injection be sometimes iterated by one only passage, the Ves∣sels creeping into every corner and secret place of the Brain and Cerebel, will be imbued with the same colour. Also in those who have the wonderful Net, the Tincture or dyed Liquor being injected in one side, it will come through the Net like infoldings of the Vessels in both sides. Hence it plainly appears that there is a communication between the Vessels watering the whole Head; and although every Artery is carried to one only Region, as its peculiar Province, and provides for it apart, yet, lest any part should be deprived of the influence of the blood, more ways lye open to every part by the ingrastings of those vessels; so that if the proper vessels by chance should be wanting in their office, its defect may presently be compensated by others neighbouring.

It is not long since we diffected the dead body of a certain man, whom a great Scirrhus or hard Swelling within the Mesentery, growing at last ulcerous, had killed. When his Skull was opened, we beheld those things belonging to the Head, and found the right Carotides, rising within the Skull, plainly bony or rather stony, its cavity being almost wholly shut up; so that the influx of the blood being denied to this passage, it seemed wonderful, wherefore this sick person had not dyed before of an Apoplexy: which indeed he was so far from, that he enjoyed to the last moment of his life, the free exercise of his mind and animal function. For indeed, Nature had substituted a sufficient Remedy against that danger of an Apoplexy, to wit, the Vertebral Artery of the same side, in which the Carotidick was wanting, the bulk of the Pipe being enlarged, became thrice as big as both its Pipes on the other side: because, the blood being excluded the Carotidick, adding it self to the wonted provision of the Vertebral Artery, and flow∣ing with a double flood into the same belly, had so dilated the chanel of that Artery above measure. This Gentleman, about the beginning of his sickness, was tormented with a cruel pain of the Head towards the left side. The cause whereof cannot be more probably assigned, than that the blood excluded from the right Carotidick Artery, when at first it rushed more impetuously in the left, had distended the Mem∣brane; and therefore the same distemper did afterwards vanish of its own accord, to wit, the superfluous blood being derived through the Vertebral Artery.

Thirdly, Concerning these sanguiferous Vessels covering the Pia Mater, we observe, that the Arteries and Veins, whilst they meet one another, going out from opposite ends, do not only transfer their burden immediately through the several branches or shoots, mutually ingrasted, as is wont to be done in other parts of the Body; but being variously complicated and interwoven, do constitute every where admirable infoldings, into which, for the most part, very small and very numerous Glandula's or Ker∣nels are inserted. Which thing is seen, not only in the infoldings, which are called Choroiedes, (by which name, besides those which are found within the plicature or folding up of the Brain, we also intend others planted together behind the Cerebel) but these kind of infoldings of the Vessels, with Glandula's sowed between, are seen every where to be sprinkled through the whole compass and interior recesses of the Brain and Cerebel, and especially between the gapings of their turnings and windings and interstices. This is clearly manifest in a moister Brain, or in an Hydropical, where the very small Glandula's, which otherwise are scarce to be seen, being intumified by the moisture, are easily beheld. Moreover, from the aforesaid infoldings, on every side implanted, little slender Vessels, being every where sent forth, enter the Cortical, and in some measure the medullary substance of the Brain and its Appendix, for if you squirt into the Carotides a black liquor, besides the shoots of the Vessels, which it dyes every where with the same colour, little blackish pricks will appear sprinkled in the substance of the Brain. Further, if the

Brain of a living Animal be cut up, the live blood will spring forth both from its Cortex and medullary part. The reason and end of all which, if they be inquired into, it seems that these foldings of the Vessels, being variously complicated with repeated windings about, as if they were little serpentine cha∣nels hanging to an Alembick, through whose narrow straits the blood passing with a long circuit, becomes still more subtil and elaborated: to wit, its thicker part, being by degrees put off in its passage, or sent away by the little branches of the Veins, and so at length the only pure and most spirituous blood, and it self now ready to go into animal Spirits, is admitted within the Pores and passages of the Brain. But as the blood or sanguinolent part is supped up by the Veins, so it's very likely the Serum or watry part is received by the Glandula's or Kernels interwoven in them. For it appears not fo•…•… what other end these Arteries are every where beset with so many Kernels, unless they should lay up in them the superfluous serosities. Between these infoldings there appear not any Nerves to be found, which may require any juyce or serous humor from these Kernels; and 'tis not yet found, whether these Lymphaeducts or Water∣carrlers be accompanied with any Vessel: wherefore it may be lawful to suppose, that whilst the purer and spirituous part of the blood, being separated from the rest of its mass, is stilled forth into the brain, the serous humidities are received by the Glandula's, which are numerous, and that they are for some time retained by them, till they may be sent away into the Veins growing empty again.

Thus far we have beheld only the superior branchings forth of the blood-carrying Vessels, which are every where interwoven in the Pia Mater; and their infoldings, which like the leaves of a Wood, or creeping Ivy, cover the exterior compass of the whole Head. But by what means, and as it were Chymical Artifice, these Vessels do instil the animal Spirits into the Brain and Cerebel, and serve for the use of one another besides, shall be •…•…old anon, after we have considered of the inferior Aspect and next the ground of this most thick Wood, viz. the greater Trunks of all the Arteries, which are destinated for the Brain, where they pass through the Skull, and shew themselves beyond it.

CHAP. VIII. Shews with what difference the Arteries in various Animals pass through the Skull; also for what use the wonderful Net is made, and the reason of it.

THE Arteries destinated to the Brain, are four in number, viz. two Carotides, and as many 〈◊〉〈◊〉. Concerning the former, we have already observed, that their Trunks pass through the Wedge-like Bone, as it were with a m•…•…chanical provision; to wit, either Artery is so bowed and intorted in its asoent, that the blood, before it can reach to the Brain by a repeated stopping of •…•…hores, or hindred by a certain let or impediment, might flow to it less rapidly and more slowly. But this is not effected after one and the same manner in all Animals: for although the ascent of the Artery be oblique and intorted in all, yet in some, viz, in a Man and a Horse, it being bowed about with a greater compass, still enters, even to the Brain, with a single and undivided Trunk: when in most other beasts the same passes the Skull with a lesser circuit, and sliding presently under the Dura Mater, 〈◊〉〈◊〉 it self there into Retisorm infoldings, commonly called the wonderful Net. Therefore it seems to be to the purpose, that we inquire into the various reasons of this difference.

In the first place therefore we shall advertise you: that the Carotidick Artery in a man enters a little more backward the Skull, than in any other Animal, viz. nigh that hole through which the lateral bo∣som slides out of the Skull about to be implanted into the Jugular Vein; for in the rest, this Artery arises within the Skull under the end or a•…•…ute process of the stony bone. But in an humane He•…•…d, the same being carried about by a longer compass, (that the Torrent of the blood, before it comes to the border of the brain, might flow slowly and plesantly with a broken force) attains to the basis of the Skull nigh the den made by the ingress of the lateral bosom; where being presently intorted, it enters the proper Chanel inscul∣ped in the Wedg-like bone, and for the greater assurance it is clothed besides with a thicker additional Coat. This double defence seems to be given it, lest the blood, boiling up too much, and whilst it is car∣ried violently towards the head, should make a Whirlpool about the ingress of the Skull, to wit, where it begins to be wreathed about from its direct ascent, and should break by its flood the bauks of the Bel∣ly, unless they were more firm. The Artery being slid out of the bony channel, lays aside also its ascititi∣ous or additional Coat; and now being well enough desended within the Skull, goes forward clothed only with its proper Coat, and creeps under the dura Mater, and being as it were depressed in the midst of its passage into a valley, being immediately carried out again, it goes on till it comes to the head of the Turky Chair, where again being bent in and intorted, with a certain compass, it ascends straight, and boring through the dura Mater, is carried towards the brain. The Trunk of this Carotis, like a Meander, passing through the Skull with a very much bending way or passage, is aptly represented in the first Figure of the following Table.

If the reason of this kind of Conformation be inquired into, it easily occurs, that in an humane Head, where the generous Affections, and the great forces and ardors of the Souls are stirred up, the approach of the blood to the confines of the Brain, ought to be free and expeditious; and it is behoveful for its River not to run in narrow and manifoldly divided Rivulets, which would scarce drive a Mill, but always with a broad and open chanel, such as might bear a Ship under Sail. And indeed, in this resp•…•…ct, a man differs from most brute beasts, in which, the Artery being divided into a Thousand little shoots, left it should carry the blood with a fuller chanel, or more quick course than is requisite, makes the Net-like infoldings, by which indeed it comes to pass, that the blood slides into the Brain very slowly, and with a gentle and almost even stream. If that be true, as some a ffirm, that the wonderful Net also is sometimes found in an humane Brain, I believe it is only in those sort of men, who being of a slender wit or unmoved dispositi∣on, and destitute of all force and ardor of the mind, are little better than dull working beasts in fortitude and wisdom.

Secondly, The conformation of the Carotidick Artery in a Horse, comes nearest its structure in a man for in this the Artery enters the Skull also lower, and with a greater compass than in other four-footed beasts: which being passed, its Trunk being intorted, with a certain compass, and then a little depres∣sed, goes forward whole to the side of the Turky Chair still with a full and broad chanel: which truly ought to be made so, because magnanimous and fierce forces are convenient for this Animal, born as it were for War and any dangerous attempts; and so there was need, that the blood might ascend the Brain with a free and plentiful course, and (when occasion requires) with a full Torrent. But though the blood passes through the Basis of a Horses Skull in the same undivided chanel, yet it ought not to come to the Brain it self in one single passage; because the frame or substance of this in a Horse being far weaker and colder than in a man, it might be overthrown and drowned by the blood rushing in by heaps: where∣fore the great River of the Artery disburdens it self by two Emissaries, and pours out its Latex at so ma∣ny distinct places of the Brain. Further, as if by this means there were not yet sufficient caution against the Deluge of the Brain, a transverse or cross chanel, as it were a diversion, is formed between the chanels of either Artery; through which the blood, being straitned for room, may go aside, and flow and re∣flow from one bank or chanel to another, rather than oppress or overflow the Brain. Also besides, cer∣tain shoots being sent out from the Trunk of either Artery, are inserted into the pituitary Glandula, the use of which is doubtless to separate certain serosities of the too watry blood, and to lay them up into that Glandula, whereby the rest of the bloody Latex, to be carried to the Brain, becomes more pure and free from dregs. By what means the Carotidick Arteries, in the head of a Horse, pass through the Basis of the Skull, is represented in the second Figure of the following Table. I have not yet had the means to inspect the brains of a Lyon or a Monkey; but there is reason to suspect, that in these also the Carotides do pass through the Skull with a single Trunk. In a Sheep, Calf, Hog, yea in a Dog, Fox, Cat, and o∣ther four-footed beasts, which I have hitherto opened, this Artery is devaricated into Net-like infold∣ings, which Vessels, for what causes and for what uses they are so made, we shall now inquire into.

Thirdly therefore, most other four-footed beasts, different from a Man and a Horse, have the wonder∣ful Net adjoyned to the Carotidick Artery. In truth, this is met within so many, that common Anatomy hath ascribed it to all Animals, and also to man it self. In whom it is found, we observe, that the Ar∣tery, about to enter the Skull, is not carried about with so long a compass, but rising up nigh the hinder part of the Turkish Chair, is presently divided into small shoots; yet so, as one little chanel is stretched right out, which the blood quietly running to, passes through without any stay, being carried straight into the Brain: but from the side of this many rivulets are derived on every side, into which the blood impe∣tuously ascending, may be easily diverted. These little rivers are partly ingrasted into the veinous passages of the same, and the Vessels of the other side, and are partly carried into the pituitary Glandula, and part∣ly a compass being fetched, are returned into the former chanel or belly of the Artery. That it is so, besides naked inspection, appears plainly by this Experiment. If below the Skull, an inky liquor be gent∣ly and by degrees injected into the Trunk of the Carotis, that passing through the straight passage, is car∣ried presently into the Brain, nor does it dye the lateral infolded Vessels with its tincture; but if this li∣quor be immitted continually and forcibly, presently running into the folds, it will make black the Vessels of the same and of the opposite side, also entring the hither part of the Glandula and its interior substance. If the use of these kind of infoldings of the Vessels, or the wonderful Net be inquired into, I say, that it is made chiefly for these ends: viz. First, that the Torrent of the blood being divided into small rivulets, its more rapid course may be so far dull'd or broken, that it may be but leisurely instilled into the Brain. For otherwise in labouring beasts, who go with their hands hanging down, and have but a weak brain, the more free influx of the blood might easily overthrow the fabrick of the Brain, and spoil the animal Spirits. Secondly, the divarication of the Carotides into Net-like infoldings, hath another use of no less moment, to wit, that the more wa•…•…ry blood being (as it is its temperament in most Beasts, and espe∣cially in those who are fed with herbage) before it be poured upon the Brain, might carry away some part of the superfluous Serum to the pituitary Glandula, and instil the other part into the branches or shoots of the Veins to be returned towards the Heart. Thirdly and lastly, for as much as the Vessels on either side are mutually inoculated by this means, there is care taken both that the blood may be exactly mixed before it ascends to the Brain, as also that more certain ways may be made for its passage: because, if per∣chance an obstruction should happen in one side of the wonderful Net, the blood by that infolding being

GG. p. 71.

[illustration]

Fig. I

[illustration]

Fig. II

[illustration]

Fig. III.

[illustration]

Fig. IIII.

presently carried to the other, may find a passage: for this cause, to wit, that the blood might be the better prevented from any impediment in its passage, the Vessels are not only inoculated under the Dura Mater about the wonderful Net, but the Arteries again on either side, do the same thing as soon as they' being knit to the Pia Mater, reach the superficies of the Brain, as hath been already shewn. By these sort of ingraftings of the Vessels in the wonderful Net, it comes to pass, that an inky liquor being injected into one of the Carotides, and forced upwards, descends by the Trunk of the Artery on the opposite side, as we have elsewhere observed. Some rude draught of the wonderful Net is expressed in the third Figure of the following Table.

The First Figure

Shews the ascent of the Carotidick Artery, and its situation within an humane Skull, before it is carried to∣wards the Brain.

• A. The Trunk of the Artery ascending towards the Skull.
• BB. The same, whilst it is included in the bony Chanel, being clothed with an additional Coat.
• C. The incurvature or bending of the Artery, reaching within the bosom of the Skull representing the bending of a double S.
• D. The Trunk of the same being carried towards the Brain.

The Second Figure

Shews the ascent of the Carotidick Arteries, and their situation in a Horses Skull.

• AA. Either Carotidick Artery ascending towards the Skull.
• BB. The Trunk of either, having past the Skull, pressed down as it were into a va•…•…y.
• CC. The communications of either by cross Branches.
• DD. A Branch from either Trunk destinated for the Dura Mater.
• dddd. Little shoots on either side sent into the pituitary Glandula or Kernel.
• EE. FF. Either Carotidick Artery being divided before it reaches the Brain, and ascending with a doubl•…•… Trunk.

The Third Figure

Shews the wonderful Net with the pituitary Kernel in a Calfs Skull.

• A. a. The direct Chanel of the Artery.
• B. The Net-like Infoldings of the Vessels stretched out by that Chanel towards the pituitary Kernel.
• C. The pituitary Glandula or Kernel.

The Fourth Figure

Shews after what manner the lateral Bosom goes into the Jugular Vein with a diverting place hanging to it.

• A. The lateral Bosom descending.
• B. That Bosom sliding into the Skull, and dilating it self into a large and round Cavity, for the receiving of which there is a peculiar Den formed in the outward part of the Skull.
• C. The aforesaid Cavity or diverting place, in which the blood to descend, may go afide, left it should else rush too strongly upon the Jugular Vein; by which also care is taken, that the blood may not flow back or regur∣gitate out of the Jugular Vein into to Bos•…•…m.
• D. The beginning of the Jugular Vein.

But as the Carotides (of whose office and ascent we have hitherto spoken) carry the destinated Tribute of the blood to the Brain; so the Vertebrals serve chiefly for the watering the Cerebel and the hinder part of the oblong Marrow. Hence we observe, because the conformation of the Cerebel is alike in Crea∣tures, therefore also the Vertebral Arteries, different from the Carotides, are found alike in all without any great difference. Nor does there seem to be need of any great provision for the admission or entrance of the Vertebral Arteries within the Skull; because, as they carry a lesser portion of the blood, and for that the Blood it self that is bestowed on the Cerebel, is wont there to be agitated or moved with no perturba∣tions of passions or conceptions; therefore there is not that necessity that there should be placed any remora or any incitement for its Torrent.

The Vertebral Artery, arising from the branch in the fifth Rib, in its whole ascent through the hin∣der part of the Head, passes through the little holes cut in the extuberances of the Vertebrae, till it comes near the Basis of the hinder part of the Head; where the same being bent down on either side, and admit∣ted into the Skull by the last hole, excepting where the spinal Marrow goes forth, is carried by the side of the oblong marrow; but as soon as it is brought to the region or the Cerebel, it sends forth branches on either side, which cover its superficies, and besides on its back fide make infoldings no less signal than

those commonly called the Choroeides, and with larger Kernels more thickly interwoven. As those shoots convey the Juyce requisite for the stilling forth the animal Spirits, so these convey the heated blood and the purified from the serous Colluvies. Further, beneath the Cerebel, both the Vertebral branches, inclining mutually one to another, are united, as it were for that end, that if the flowing of the blood should be stopped on either side, it might be supplied from the other to the whole compass of the Cerebel and its neighbouring parts. These sanguiferous Vessels covering the Cerebel, even as the others do the Brain, make signal in foldings both in its outward superficies, and in that of the oblong marrow, and also with∣in its lappets and folds; from which small shoots are sent forth every where into its under-lying substance: so that from these a subtil liquor, as it were stilled forth and imbibed by the Cortical substance of the Ce∣rebel, seems to go into animal Spirits. By what means, and in what parts of the Head the production of the animal Spirits is performed, remains next to be inquired into.

CHAP. IX. Shews by what provision, and in what places of the Head the Animal Spirits are begotten: Also other Uses and Accidents of the Pia Mater are added.

FRom the description of the Sanguiducts or Blood-carrying Vessels, which cover and weave about on every side the Pia Mater, hitherto handled, we are led by a certain thread to consider by what provision, and in what places of the Brain and its Appendix the production of the animal Spirits is performed.

1. As to the first, it appears from what hath been already said, that the blood is it self the matter out of which the animal Spirits are drawn; and that the Vessels containing and carrying it every where through the whole compass of the Head, are like distillatory Organs, which by circulating more exactly, and as it were subliming the blood, separate its purer and more active particles from the rest, and subtilize them, and at length insinuate those spiritualized into the Brain and its Appendix. Concerning this mat∣ter to be distilled, there is care taken, and indeed by the best means, that its stock or provision may be still supplied in fit quality and due quantity.

In respect of the quality, from the whole bloody mass, a portion highly volatile, spirituous, and endu∣ed with active Elements, ought constantly to arise towards the Head; which thing succeeds partly of its own accord, and partly that it might be more commodiously done, care is taken with a certain artificial∣ness; to wit, the Vertebral Arteries, in all Creatures ascending straight, and almost perpendicularly, do in a manner cause, that only the more subtil and light blood is carried upwards, the remaining more thick as it were sinking down for the baser offices of the Limbs and of some of the Bowels. Yea, also the Carotides in a man, having an erected head higher than the rest of the parts, and in a Horse in some sort lifting up his face, have also the same priviledge; to wit, that by their more steep ascent only the more pure and volatile blood may ascend to the region of the Brain. But in other four-footed beasts, who go with a prone or hanging head, and who have a more frigid and watry blood, which may easily slide into, and too much wash the Brain, this evil is in some part prevented by the wonderful Net and pitui∣tary Gla•…•…dula joyned to the Carotides; which indeed receive the superfluous humidities of the blood, and and so make it more pure and free from dregs before it comes to the brain.

But that the blood may be supplied still in due quantity, to wit, as it were in weight and measure, from the distillatory Vessels, stretched about the compass of the Head, there is a notable provision made in all the Carotides about the Basis of the Skull: because their crooked imbowings and branching into infold∣ings, hinders the too great or too rapid approach of the blood: then, lest the passage of it should at any time be s•…•…ut up, the mutual ingrastings of all the Vessels on either side, do help or provide for. After this manner, the business of extracting the animal Spirits is performed even as a Chymical Elixir; to wit, great car•…•… is taken in the beginning of that Operation, both that choice of matter may be had, and that only a d•…•…e proportion of it be exposed to the distillation.

The blood by this means, as it were a Chymical work prepared, is carried by the fourfold Chariot of the Arteries to four distinct regions of the Head: and as the sanguiferous Vessels, being distributed with separate ramifications or branches through the whole compass of the Brain and its Appendix, cover all the heights of its compassings about or gyrations, and also its crevices and their gapings and recesses, they bring to their doors the matter to be distilled into the Head every where through the whole cir∣cumference of the Brain and Cerebel nigh the Cortical substance of either; out of which as the Spirits are distilled, by this means it is brought about, that they are insinuated into the subjected substance of either. The blood being carried through the narrow infoldings and divarications of the Vessels as it were (as was said) through the serpentine chanels of an Alembick is made extremely subtile,

as much as may be, in its liquor; in the mean time, what is bloody is received by the little shoots of the Veins associates; or meeting one another every where, and what is serous by the Kernels every where dispersed; yet its more purified and spirituous part being carried on further through the very small shoots sent forth on all sides, are instilled more deeply into the very Pores and passages of the Brain and C•…•…rebel; which presently flowing from the Cortical substance into the medullary, there exercise the gifts of the ani∣mal Function. What peculiar body and constitutive particles of the Brain it self and Cerebel, conduce to the generation and perfection of the animal Spirits within the substance of either, shall be shewn hereafter, when we treat of the Use of those Parts: now shall be taken notice of what we before mentioned, to wit, that the fluid extillation of the spirituous liquor from the blood about the Pia Mater, is performed after a signal manner, both from the ambient heat, which is stirred up from the blood contained within the bo∣soms, as it were from a Balneo Mariae, inriched by the continual flowing of it anew, and also from the obduction of the Meninges, like an Alembick, by which the spirituous Particles, apt to fly away, are constrained and forced into the parts beneath.

But indeed, though the animal Spirits are procreated wholly from the blood, yet the blood watering the Brain and its Appendix, is not only bestowed on this work: for as to the sanguiferous Vessels, which arising out of the Trunks both of the Carotides and the Vertebrals, cover over the whole Head and all its parts and processes; though many of them, yet not all, are little distillatory chanels of the animal Spi∣rits. For the animal Spirits are not produced in all places, to which these Vessels reach, for we affirm, that these Spirits are only procreated in the Brain and Cerebel: (which it were easie to prove by the Symp∣toms which happen in the Apoplexy and Palsie, and shall be afterwards clearly shewn) and from this double fountain of the animal Spirits they flow out into all the rest of the parts, and irradiate, by a con∣stant influence, the whole nervous stock. In the mean time, the oblong marrow and its various processes and protuberances are either retreating places, or high roads for the animal Spirits, procreated in the Brain and Cerebel, and flowing from thence. But for as much as the Arteries and Veins clothe these parts also with a thick series of shoots, and that within the infolding of the Brain the solds called Choroeides are hung slack and loosly, these seen to be so made for other reasons, viz. both that these parts might be actuated by heat, supplied as it were from a continual fire, and also that the nourishing Juyce might be bestowed on the Spirits which flow there.

As to the first, that the animal Spirits now perfected, may be freely expanded, and irradiate the ner∣vous System, there seems to be required, that the ambient heat, being excited by the blood flowing thi∣ther, might open all the little spaces for their passage, and notably dilate or lay open for them ways or roads: wherefore we intimated before, because the little shoots of the Vessels ought not to be deeply in∣serted into callous body, (for that, left the commerce of the Spirits, diverting in this Mart or meeting place, should be disturbed by the perpetual influence of the blood) therefore the infolding of the Choroeides is hung under its chamber, that at least by this nigh situation, as by a Stove or Hot-House, the heat there might be preserved. Besides, we intimated another use of this infolding; to wit, that the blood, passing through the very narrow Meanders and convolutions or rollings about of the Vessels, might lay aside its serous recrements into the Glandula's or passages of the Veins.

2. But secondly, That many branches and lesser shoots of the same Vessels, which water the Brain and Cerebel, cover also the oblong marrow, and in some measure enter into its Pores and deeper substance (within which the animal Spirits are not begotten, but only exercised and expanded) I say, that this is so made for this other respect; to wit, that the substance of the oblong marrow might imbibe a con∣stant provision of nourishment from the pouring in of the blood whereof it hath need. For whilst the ani∣mal Spirits, flowing into the nervous stock from the Brain and Cerebel, pass through this passage, as it were the high road, some food here ought to be administred to them, as it were in their journey, from the water∣ing blood: For indeed we suppose (which also will afterwards clearly appear) that the oblong marrow, together with the nervous parts, is moistned with a double humor, viz. one spirituous and highly active, which flows altogether from the Brain and Cerebel, and being from thence derived into the whole ner∣vous stock, bestows upon them the sensitive and moving Faculties; and the other humor softer and more oily and sulphureous, which being supplied from the blood, and affused immediately on every part, is the Author of their Heat and Vegetation. Both these Juyces agree among themselves, and being every whe•…•… joyned together and married, they are as it were a masculine and feminine seed mixed together, and so they impart to all parts both sense and motion, and all the powers of life and growth. Wherefore it is observed, that all the parts of the whole body, by which motion and sense are performed, do not only swellup with the animal Spirit, of whose influence being deprived, they presently suffer a resolution or loosning; but also they admit the sanguiferous Vessels; of whose Tribute if they be defrauded, presently they wither away, or are distempered with a mortification or Gangrene. Wherefore, that the flesh, mem∣branes, and all the bones may be watered with the blood, (as may be perceived by the help of a Mi∣croscope) the very little or minute bodies of some of the Nerves are surrounded with Capillaments or little hairs of Arteries and Veins, together with their proper Fibrils, that we need not doubt to assert that the Vessels penetrating the superficies of the Brain and Cerebel, do distil into them a subtil matter for the generation of the animal Spirits; but that some other shoots of the same Vessels, covering the ob∣long marrow, do only impart to it heat and nourishing Juyce. Lastly, that the infoldings of the Choroeides were built under the chamber of the oblong marrow, chiefly for the dispensing of heat,

and in some measure for the sake of separation of the serous Latex. But concerning these, we shall have oc∣casion to speak more largely afterwards, when we shall treat of the nutritious and nervous Juyce, and when we shall consider of that famous Controversie, viz. whether nourishment is made by the blood or Nerves: further, we shall elsewere speak more fully of the Nature, Hypostasis, and diverse Disposition of the animal Spirits; also, what the substance of the Brain, and the conformation of the parts, may contribute to their production.

Thus far concerning the Pia Mater and the blood-carrying Vessels, which are woven in it, and follow∣ing its protension, water the whole Head, we have treated largely. But before we quite leave the con∣sideration of this Membrane, we will inquire what sense and motion it may have. Certainly it is not un∣deservedly that weascribe the most cruel Head-aches to the more acute sense of this; (in which however, by what means this Meninx is affected, does not so easily appear.) It is the common opinion, that sharp and tormenting Vapours, being raised from the Viscera of the lower Belly, especially from the Ventricle, Hypochondria, or Womb strike against this Membrane, and so pierce it with a pain. But we say, though this be impossible, that Vapours passing so many interstices and bars of the Viscera and bones, without any trouble, should ever come to the Head and hurt it: yet we do not deny, but that sometimes vaporous Effluvia's do proceed from the blood boiling or estuating within the confines of the Brain, which being shut up together under the Pia Mater, and as it were gathered into a Cloud, do greatly blow up and distend it, and so-distemper it with pain. I have often seen, in a Head newly opened after death, the Pia Mater distended, and shining like a Bladder, that the same seemed to be intumified, with much water in∣cluded under it; which notwithstanding was found to be so done by wind distending the Membrane, for that being diffected, that Tumor fell down without the effusion of water.

But we think the Head-aches, which happen by reason of the evil of this Membrane, are chiefly ex∣cited by another means, to wit, for as much as this Meninx suffers a breach of the unity by the blood boi∣ling up above measure, and rushing into its Pores, and so it is contracted into lighter Convulsions. I have sometimes opened the Heads of the defunct, which when living, were obnoxious to most miserable Head-aches; in which, near the longitudinal bosom, where the seat of pains was, the Pia Mater or interi∣or, grew to the Dura Mater or exterior for some space, oft-times for two fingers breadth, and by their growing together had excited a sharp and unequal Tumor; in which the mouths of the Vessels were so wholly stopped up, that there was left for the blood, though very much boiling up, no passage into the adjoyning bosom.

As to the motion of this Membrane, we wholly deny, that it hath in it self a perpetual Systole and Diastole; however, the Pulses in some Arteries, have seemed something like it, which have given occa∣sion perchance to this vulgar Opinion. Yet in the mean time, it may be lawful to believe, that this Men∣inx, for that it is very sensible, is rendred obnoxious to Cramps and convulsive motions: and from its greater contraction the fits of the Falling-sickness do arise, and from its lesser and more partial corrugation or wrinkling together, Head-aches, as hath been said, and also sometimes Scotomies, Vertigoes, and often Convulsions of the Members and Viscera, planted at a great distance from the origine of the Nerves, being drawn into consent.

CHAP. X. A Description of the Brain, properly so called, and the Explication and Use of its Parts.

WE have thus far beheld the Coverings of the Brain, both the bony and the membranous, also the Arteries and Veins growing and knit to them, like Ivy, and distributed through the whole compass of the Head. Therenow remains, these coverings being removed, that we next consider the Fabrick and true Hypotype or Character of the Brain and its Appendix, to∣gether with the action and use of all the parts. And here at first sight we meet with three things, to wit, the Brain, the oblong Marrow, and Cerebel: of which the oblong marrow seems to be a common Trunk, to which the Brain and Cerebel grow like branches: wherefore some contend the medullary Rope to be the principal part, and the Brain and Cerebel its dependences. But that it is otherwise ap∣pears by this, because these bodies, both in the generation and dispensation of the animal Spirits, are of more noble use than the oblong marrow; so that if the out-flowings of the Spirits from the Brain or Ce∣rebel be shut up or hindred, the nervous System presently suffers an Eclipse; in the mean time, if this be primarily distempered, the Braio and Cerebel suffer not for its fault.

That we may begin with the Brain, it may be considered in a double respect; to wit, both as to i•…•…s convex or exterior superficies, as it is beheld in its proper site and position; and as to its interior cavity, to wit, as the Brain appears opened, its concave superficies being expanded and turned upside down. We have already taken care to delineate its true form or Type in either manner, by what hath been be∣fore said, to wit, after what manner it is both within and without. There now remains, after its fabrick and conformation being rightly weighed, for us to design its offices, and to shew the uses of it and of e∣very one of its parts. Concerning which, we ought to unfold in general, first, what the office of the whole Brain is; then secondly, when we shall descend to particulars, there will come under consideration, 1. The division of the Brain, to wit, its double Hemisphere, also the two Lobes or partitions of either. 2. The narrow crankling turnings and windings, or the gyrations and convolutious or rolling together of the Brain. 3. Its double substance, viz. Cortical and Medullary. 4. The common Basis of all, viz. the callous body. 5. Its subtension or Fornix. 6. The appension or circuit of the Brain over or above the eblong marrow. 7. And what results from thence, the void space or Ventricles made by its infolding together. Concerning these, we shall take notice of what things occur worth noting; concerning the smelling Nerves and their processes, we shall inquire afterwards, when we shall speak particularly of the Nerves.

1. The Brain is accounted the chief seat of the Rational Soul in a man, and of the se•…•…sitive in brute beasts, and indeed as the chief mover in the animal Machine, it is the origine and fountain of all moti∣ons and conceptions. But some Functions do chiefly and more immediately belong to the substance of this, and others depend as it were mediately and less necessarily upon it. Among these, which of the for∣mer sort are accounted the chief, are the Imagination, Memory, and Appetite. For it seems, that the Ima∣gination is a certain undulation or wavering of the animal Spirits, begun more inwardly in the middle of the Brain, and expanded or stretched out from thence on every side towards its circumference: on the contrary, the act of the Memory consists in the regurgitation or flowing back of the Spirits from the ex∣terior compass of the Brain towards its middle. The Appetite is stirred up, for that the animal Spirits, being some-how moved about the middle of the Brain, tend from thence outwardly towards the ner∣vous System. The rest of the Faculties of this Soul, as Sense and Motion, also the Passions and Instincts merely natural, though they depend in some measure upon the Brain, yet they are properly performed in the oblong Marrow and Cerebel, or proceed from them.

2. In some Animals, the substance of the Brain is divided into two parts, as it were Hemispheres, distinct one from another almost through its whole thickness, even to the callous body, which is instead of a bottom; and in like manner also in all the Sensories, and in most of the other Organs of the necessa∣ry Functions, the Brain is as it were twofold, that there might be a provision made against the defect of one side by the supplement of the other. Further, in man, who hath a brain morelarge and capacious than other Creatures, either Hemisphere is again subdivided into two Lobes, to wit, the Anterior and the Posterior; between which a branch of the Corotidick Artery, being drawn like a bounding River to both, distinguishes them as it were into two Provinces. Certainly, this second partition of the humane Brain also seems to be designed for its greater safety; that if perchance any evil should happen to one or both the foremost Lobes, yet the latter, for that they are separated, may avoid the contagion of the neighbouring and farther spreading evil: So the Brain, like a Castle, divided into many Towers or places of Defence, is thereby made the stronger and harder to be taken.

3. Also the universal frame of the Brain appears yet more divided and variegated within all its afore∣said partitions; for all its whole exterior superfices is made uneven and broken, with turnings and wind∣ings and rollings about, almost like those of the Intestines. Those Gyrations or Turnings going from the fore-part of the Brain towards the latter with a creeping compass, and as it were a spiral circuit, encom∣passes both its Hemispheres, that they mighty mutually furnish all the convolutions with a continued passage: in a more moist Brain, or long kept, the Pia Mater, clothing every one, and collecting them to∣gether is easily pulled away; and then the turnings or folds being opened and separated one from another, the substance of the brain is seen to be plowed, or laid as it were with furrows; out of which arise banks or ridges of broken crevices, not in a direct series, but cross-wise; so that the bottom of every furrow, a convultion arising from the right side, is carried to the left; then others following next, being sent from the left side, is drawn to the right, and so by turns the inequalities of the whole brain are variegated in this order.

If it be inquired into, what benefit its Turnings and Convolutions afford to the brain, or for what end its whole anfractuous or broken crankling frame is, we say that the brain is so framed, both for the more plentiful reception of the spirituous aliment, and also for the more commodious dispensation of the animal Spirits for some uses. As to the aliment to be bestowed on the brain, because it is required to be subtil and extremely wrought or elaborated; therefore it ought to be admitted, not by a more open pas∣sage, but only by very small pores and passages. Wherefore that there might be sufficient plenty of spiri∣tuous liquor supplied, it is not only drunk in every where in the plain superficies of the brain from its Cortical substance; but that superficies of the brain or Cortical substance is uneven and rough with folds and turnings about; that the spaces for the receiving the Juyce might be enlarged as much as may be: For the anfractuous or crankling brain, like a plot of ground, planted every where with nooks and cor∣ners, and dauks and mole hills, hath a far more ample extension, than if its superficies were plain and even

Further, those cranklings of the brain do more fitly hide the sanguiferous Vessels, for that they are very small and slender, and more safely keep them, being variously interwoven into one anothers infoldings, than if they should be openly distributed; for so being carelesly laid, they would be liable to too frequent hurt.

But a reason and necessity of the turnings about the brain, and not of lesser moment than the other, is fetched from the dispensation of the animal Spirits. For as the animal Spirits, for the various acts of Imagination and Memory, ought to be moved within certain and distinct limited or bounded places, and those motions to be often iterated or repeated through the same tracts or paths: for that reason, these manifold convolutions and infoldings of the brain are required for these divers manners of ordinations of the animal Spirits, to wit, that in these Cells or Store-houses severally placed, might be kept the species of sensible things, and as occasion serves, may be taken from thence. Hence these folds or rollings about are far more and greater in a man than in any other living Creature, to wit, for the various and mani∣fold actings of the superior Faculties; but they are garnished with an uncertain, and as it were fortui∣tous series, that the exercises of the animal Function might be free and changeable, and not determined to one. Those Gyrations or Turnings about in four footed beasts are fewer, and in some, as in a Cat, they are found to be in a certain figure and order: wherefore this Brute thinks on, or remembers scarce any thing but what the instincts and needs of Nature suggest. In the lesser four-footed beasts, also in Fowls and Fishes, the superficies of the brain being plain and even, wants all cranklings and turnings about: wherefore these sort of Animals comprehend or learn by imitation fewer things, and those almost only of one kind; for that in such, distinct Cells, and parted one from another, are wanting, in which the divers Species and Ideas of things are keptapart.

But that in more perfect Animals, all the turnings about are made of a twofold substance, viz. Cor∣tical and Medullary: the reason seems to be, that one part may serve for the production of the animal Spirits, and the other for their exercise and dispensation. For we may well think, that the animal Spirits are wholly or for the most part procreated in the Cortical substance of the brain; for this severs and receives immediately from the blood the subtil liquor, and imbuing it with a volatile Salt, exalts it into very pure Spirits. It is obvious to every one, that the Arteries enter the Cortex of the brain with a more fre∣quent insertion of shoots, and instil to it a spirituous liquor; the leavings of which, or what is super∣fluous, the Veins in like manner entring it, do sup up and carry away; in the mean time, the more subtil portion being here set free, goes into Spirits. In truth, the blood waters the medullary substance of the brain in a very small quantity; which seems truly to be rather for the sake of exciting of heat, than that the animal Spirits should there be generated by the flowing in of that blood. For indeed, the volatile Salt, which like Ferment, spiritualizes the subtil liquor stilled forth from the blood, is had more copoiusly in the Cortex of the brain, rather than in its mdidle or marrowy part; because that part being en∣dued with an Ashy colour, shews by its aspect the spermatick Particles and Humor contained in them, in which Spirit and a volatile Salt very much abounds; yea and plainly resembles on Armeniack smell, (such as either part alike breathe forth.) In the mean time, the medullary part of the brain seems very like the oblong marrow and the spinal. But it is well enough known, that these medullary parts serve for the exercise and dispensation of the animal Spirits, and not for their generation. The sign of which is, that where-ever an obstruction happens in them, whatever is below, being destitute of the influx of the Spirits, suffers an Eclipse; whence it follows, that the animal Spirits, irradiating the medullary Rope, are not produced in it, but flow in from elsewhere; and why should we not think the same of the middle marrow of the brain? Truly, that this part is rather the Mart or Exchange of the Spirits than its Shop or Work-house, appears from hence, because the Animals which excel in Memory, Imagination, and Ap∣petite, are furnished with a more ample marrow of the brain; as is observed in man and the more perfect four footed beasts: and they who seem to have little need of those Faculties, as the lesser four∣footed beasts, also Fowls and Fishes have the Cortex of the brain greater, but the medullary part very small. It is a familiar Experiment among Boys to thrust a needle through the head of a Hen, and that she in the mean time, whose brain is so pierced through, shall live and be well a long time. The reason of which is, because the whole substance of the brain in these sort of Animals is almost merely Cortical; wherefore from the suffering such a hurt, (as long as the marrow remains unhurt) the Spirits are gene∣rated in a lesser quantity, but their commerce to the necessaries of life, are not therefore presently interrupted. Indeed the brains of Birds consist almost wholly of a Cortical and Ashy part; and the medullary part is exceeding small, and is only like a smaller Nerve descending on either side from the substance of the brain it self.

After the animal Spirits are begot by a constant afflux of the blood within the Cortex of the Brain, be∣ing there begotten, having obtained a watry Vehicle, they flow presently more inwardly, and soon enter into the marrows, filling the furrows and baulks of all the turning and winding Crevices; from whence being carried farther through all the particular tracts of each marrow into the marrowy substance, which lyes under all the winding Crevices, as their common Basis, they are brought at last into the Callous Body, as into a spacious field; where, as in a free and open place, these Spirits being newly produced, are ex∣patiated or issue forth.

[illustration]

Fig. VII.

HH. p. 77.

5. Indeed this medullary substance called the Callous Body, which chambering the more inward super∣ficies of the brain, receives into itself the marrow of all the turning Crevices, seems to be made for that end, and disposed there for the same purpose; to wit, that the Spirits flowing into it on every side, might be stretched out as in their proper Sphere, and begin to exercise the acts of the animal Faculties. In this place, they which come out of the several winding Crevices, do meet together, and remain as in a pub∣lick Emporium or Mart; from whence, as occasion serves, they are raised up, and drawn forth for the uses of every Faculty. But whilst they here remain at leisure and not busied, they become purified or refined more and more by a continual circulation: because these Spirits new-born, do gently and perpetually flow on every side from the outmost bounds of this body (to wit, where this common marrow be∣smears the hinder productions of the brain, or the border of either of its Hemispheres) towards the fore∣part of this callous Body, where it is thickest; and there, if there be need, they are employed on the act of the Imagination, or entring the shanks of the oblong Marrow, they actuate and inspire the nervous Ap∣pendix: but what Spirits are remaining there, after these offices are served, run forthwith into the Fornix, and passing through its passage, they are remanded back again to the hinder region of the brain by a certain circulation; and lastly, after this manner, penetrating through the narrow passages of the Fornix, those Spirits are made more subtil, and also, as it seems most likely, they perform in this circulary motion those more subtil acts of the Phantasie.

6. Truly, that we may here speak something of the Fornix, it seems that this part serves for a towfold use: viz. first, lest more inward sides of the Brain hanging slack and loosly, might fall together among themselves, or might be removed beyond the limits of a just protension or out-stretching; for they not only by the coming between of the Pia Mater, and by little cords drawn from it, cohere to the ob∣long marrow and the Cerebel; but besides, the Fornix, like a Ligament or string brought from one end of the brain to the other, constrains and keeps its whole frame in its due figure and situation. For this part purely medullar, and of the same substance with the callous Body, seems to be a certain process of this, which arising more forward between the streaked bodies, and falling upon the two shanks of the o•…•…∣long marrow, first of all distinguishes them: afterwards, being separated from them, is carried through the midst of the cavity, and about the hinder part of the brain is divided as it were into two Arms, which being bent on both sides, and again cleaving to the border of the callous Body, strictly embrace the oblong marrow, and knit and firmly tye the hinder bulk of the brain to its Trunk, left it should flow or slide forth. But the other, and that the more noted use of the Fornix seems to be what we but now menti∣oned; to wit, that the animal Spirits may immediately pass through its passage from one end of the brain to the other, and so, as it were through the bill of a Pelican▪ they might be circulated into their own intorted belly.

That those things were but now declared concerning the Penetralia and inward recesses of the Brain, may be the better understood, we will here add a Scheme of its Sphere turned inside out, and stretched out as it were upon a plain, so that the concave and inmost superficies of the callous Body, together with the Fornix, may be sufficiently seen.

The Seventh Figure

SHews the Brain of a Sheep bent back and out a little open in the places where they stick together near the streaked bodies, that its interior substance may be tur•…•…ed the inside out, and unfolded on a plain.

• AA. The substance of the Brain cut asunder, which in its natural sit•…•…ation being folded together, did cohere with the rest of its substance a. a. upon the remaining streaked Bodies.
• B. The Trunk of the Fornix or Psalloides cut asunder, which in its natural site coheres with the Basis of the some Fornix E.
• CC. The Arms of the Fornix which •…•…mbrace the medullary Trunk on the other side of the Pineal Glandula.
• DD. The brim of the callous Body which embraces the medullary Trunk near the Cerebel.
• E. The Basis of the Fornix.
• FF. Two straight Roots of the Fornix lying between the streaked Bodies.
• GG. The transvers•…•… medullary Pr•…•…cess knitting the two streaked Bodies one to another.
• H. The Chink near the Roots of the Fornix leading to the Tunnel.
• I. The streaked Bodies, whose Superficies the small Arteries and Veins cover over.
• KK. The interior Superficies of the callous Body marked with transverse medullary streaks or chamferatings, or reaching from one Hemisphere of the Brain to the other.
• LL. The Chambers or hollow places of the Optick Nerves.
• M. The anterior hole leading to the Ventricle lying under the orbicular Prot•…•…berances, which also goes slope-wise to the Tunnel.
• N. The Pineal Glandula which appears more plain, the Pia Mater and the Choroeidal infolding being sep•…•…∣rated and removed.
• OO. The Natiform or Buttock like Protuberances, which are here far greater than in a Man or Dog.
• PP. The lesser Protuberances called Te•…•…tes, which are additions or things growing out of the former.
• ...

• QQ. The medullary Processes stretehing from the Testes into the middle or marrowy part of the Cerebel.
• R. The meeting together of those Processes.
• SS. The Pathetick Nerves of the Eyes arising out of the meeting together of those Processes.
• T. The posterior bole leading into the Ventricle, lying under the orbicular Protuberances, and also into the same opening of the Tunnel.
• V. A Furrow in the medullary Trunk, which being covered by the Cerebel, makes the fourth Ventricle.
• WW. The Ramifications or Branchings of the medullary substance of the Cerebel, which appear like a Tree.
• X. The end of the oblong Marrow about to go into the Spinal.

CHAP. XI. Shews with what motion and tendency of the Animal Spirits, the Exercises of the Animal Faculties are performed within the Confines of the Brain: Also what the use of its Ventricles is.

HItherto setting forth the uses and offices of the Brain, properly so called, and of its parts, we have shewed after what manner the animal Spirits are procreated from the blood in this their principal Shop or Work-house; and into what diverting places, they being newly brought forth, do depart of themselves, and are there kept as it, were in distinct Cloisters or Cells to be drawn forth for the mainfold Exercises of the animal Function. But because these Spirits, so brought to perfection, and ready for their work within the same parts of the Brain, enter into other manner of motions, and divers ways of emanations; therefore before we proceed any further, for the searching out their tracts within the oblong Marrow and Cerebel, we ought to declare concerning these Spirits dis∣posed within the confines of the Brain it self, with what forces they are furnished, in what form they un∣fold themselves, and in what ways they diffuse themselves and go forward as often as being mustered in due order, they produce the acts of the Imagination, Memory, Appetite, and other superior Faculties of the Soul, But for as much as hereafter, when we have finished the explication of the Head and nervous Appendix, we have resolved, for a conclusion, to treat of the Soul of Brutes and its powers, I may there∣fore for the present lay aside this task; unless that in the mean time it may not seem amiss to give a taste only in general of these few things: viz. as there are two parts of the inferior Soul, or of Beasts, to wit, the vital or flamy, being inkindled in the blood, and the sensitive or lucid, being diffused through the whole Head and its nervous dependences, the animal Spirits being continually produced in the Brain and in the Cerebel, do constitute a double as it were Root or Fountain of this lucid part: yea, the Spirits of ei∣ther linage, for as much as they are continued both within those Fountains, and from thence through the frame or substance of the nervous System, as it were under the same beamy Systasis and contexture, they effect or cause the whole Hypostasis or subsistency of the sensitive Soul.

But there happen to this Soul, because it is apt to be moved with a various impulse, and so to contract or dilate its species in the whole, or in part, for that reason divers manners both of Actions and of Passi∣ons, to wit, the Senses, which we call its Passions; and Motions, which we name the Actions of the same. The sormal reason of the former, viz. the Senses, consists in the retraction or drawing back of the Spirits, or a flowing back towards their Fountains. For where-ever the impression of a sensible object is carried to this radiant or beamy contexture, presently either the whole frame, or some portion of it, whereby it admits the species, is compelled to wag, and to be moved back, as it were to leap back and recede into it self: on the contrary, the actions or motions of this Soul are made, for that this shadowy Spirit, being incited or stirred up in the whole, or in a certain part, unfolds it self more largely, and by an ema∣nation, and as it were a certain vibration of the Spirits, exerts or puts forth its virtue and force of acting.

Both the Senses and Motions of this sensitive Soul are made either transient, when the Spirits, or its constitutive Particles, being moved somewhere in the System of the Nerves, draw together with them the containing parts, and deflect them with the like carriage or gesture with themselves, as is observed in the five outward Senses, and the local motions of the Members: or else, either both Actions and Passi∣ons are continuing, to wit, when both the Motions and Senses are silently performed without any great a∣gitation or moving of the body, or its parts, within the first Fountains of the Soul, viz. the Head it self. These kind of Passions indeed, made within the substance of the Brain, are the common Sense and Imagi∣nation; but the Actions are Memory, Phantasie, and Appetite: and either of these, as to their beginnings and instincts, depend for the most part upon the outward Senses.

Concerning the former, we take notice, that as often as the exterior part of the Soul being struck, a sensible impression, as it were the Optick Species, or as an undulation or waving of waters, is carried more inward, bending towards the chamfered bodies, a perception or inward sense of the Sensation out∣wardly had or received, arises. If that this impression, being carried farther, passes through the callous Body, Imagination follows the Sense: Then if the same fluctuation of Spirits is struck against the Cortex of the Brain, as its utmost banks, it impresses on it the image or character of the sensible Object, which, when it is afterwards reflected o•…•… bent back, raises up the memory of the same thing.

The active Powers of this Soul, viz. Local Motion, Memory, Phantasie, and Appetite follow some∣times immediately the Passions, sometimes are induced apart from them upon other occasions. For in∣deed the sensible impression striking the streaked or chamfered bodies, oftentimes, the Brain being in no wise affected, causes the local Motions to be retorted with a reciprocal tendency of the animal Spirits; so in sleep (the Appetite knowing nothing of it) when pain troubles, presently we rub the place, mo∣ving the hand to it: but more often, after that the sensible Species, having past from the common Sen∣sory to the callous body, hath stirred up the Imagination, the Spirits, reflecting from thence, and flowing back towards the nervous Appendix, raise up the Appetite and Local Motions, the Executors or Performers of the same: And sometimes a certain sensible impression, being carried beyond the callous Body, and strik∣ing against the Cortex of the Brain it self, raises up other Species lying hid there, and so induces Memory with Phantasie, also often with Appetite and Local Motion associates. Further, these active Powers, sometimes upon other occasions, are wont to be stirred up and exercised apart from Passion. In Man, the Rational Soul variously moves the sensitive, and at its pleasure draws forth and brings into act its Pow∣ers, sometimes these, sometimes those. Moreover, the blood boiling up above measure, and by that means striking impetuously the border of the Brain, excites the species of things lurking in it, and driving them forward towards the middle or marrowy part of the Brain, causes also the various Acts of the Phantasie and Memory to be represented.

Concerning the aforesaid interior or abiding Faculties, we shall at present further take notice, that their more perfect Exercises are chiefly and almost only performed by the Spirits already perfected and highly elaborated; for those a making, or that are new made, being numerous, they very much obstruct and hinder the acts of the animal Function: to wit, when from the Vessels, on every side watering the Cortex of the Brain, the subtil Liquor is plentifully instilled for the matter of the Animal Spirits, this flowing in∣wardly stuffs all the pores and passages of the Brain, and so excludes for that time the Spirits from their wonted tracts and orbs of expansion. Wherefore whilst the chief reflection of the Brain and Spirits is ce∣lebrated, sleep, or an Eclipse of the animal Spirits happens; then waking returns, when from the Liquor instilleds the more subtil part is exalted into very pure Spirits, and at length the more watry, being partly resolved into Vapours, is exhaled, and partly supped up by the passages of the Veins entring the substance of the Brain, or else is sweat out into the vacuity lying under the callous Body. Con∣cerning these I hope we may discourse more largely afterwards. In the mean time, that we may proceed to the rest of the things proposed, concerning the frame of the Brain, properly so called, there yet remains that we speak of its Ventricles: But since they are only a vacuity resulting from the folding up of its ex∣terior border, I see no reason we have to discourse much of their office, no more than Astronomers are wont of the empty space contained within the vacuity of the Sphere.

But in truth, as there is nothing met with in Nature that is not destinated to some use, surely we sus∣pect this same Vacuum or empty space not to be built in vain within the Globe of the Brain. The An∣cients have so magnified this Cavern, that they affirmed it the Shop of the Animal Spirits, both where they themselves were procreated, and performed the chief works of the animal Functiou. But on the other side, the Moderns or those of later days have esteerned these places so vile, that they have affirmed the same to be mere sinks for the carrying out the excrementitious matter. But indeed that opinion of the Anci∣ents is easily overthrown, for that the animal Spirits, being very subtil, and apt to fly away, require not such large and open spaces, rather than the more narrow passages and little pores, •…•…uch as are made in the substance of the Brain: for these Spirits (because they ought, for the various Faculties of the Soul, to be com∣posed into various series, and divers orders and dispositions, therefore) ought to be moved within pecu∣liar orbs and tracts Further, if any one shall exactly consider the fabrick of the Brain, and seriously weigh, that these Ventricles are not formed out of the primary intention of Nature, but result only secondarily and accidentally from the complication of the Brain, he will be far from thinking, that the supreme seat of the Soul is fixed there, where being hem'd in with a most noble Guard of Spirits, it doth execute and perform its Functions. For it neither appears at all out of what matter, and by what artifice the Spirits are there begotten, nor by what ways of emanation they are derived from thence into the other parts of the Brain and nervous System. Wherefore almost all Anatomists, who are of a later Age, have attributed that vile office of a Jakes or sink to this more inward chamber of the Brain. To which Opinion there has been some trust given, for that these Ventricles are often seen in the dead to be filled with water, alsofrom these, ways seem to lye open for excretion, both towards the Tunnel, and also into the Sieve-like Bone. It is observed, that where-ever the blood flows more copiously into any part, and waters it, there Vapors or watry Humors are begotten from the superfluous Serum left in the circulation, which for the most part either exhale out through vaporous Effluvia's, or are brought back into the blood by the Veins or Lym∣phatick Vessels. But when the blood, by a plentiful influx, waters not only the Cortex of the Brain, but

the interior marrow also, it remains, that the serous Latex (when-ever it abounds more in the blood, than that its superfluities may be reduced immediately by the Veins, or by the Lymphaeducts, if they be there, or may be separated by the Glandula's) should slide down into this den, made hollow within the infolding of the Brain. Truly there are many instances, which plainly evince, that the serous humors are ordinarily laid up in the Ventricles of the Brain. Anatomical Observations of men dying of many Cephalick diseases, and especially of soporiferous or sleepy distempers, confirm this. Yea, it may be lawfully thought, that natural sleep follows, for that the Pores and passages of the Brain are occupied and stuffed with a watry-Latex, which serves for a Vehicle to the Spirits. Then as often as a profound sleep invades any one from a Surfeit, or drinking of Wine, the cause is, that the little spaces in the medul∣lary substance of the Brain, destinated for the motions of the Spirits, are too much obstructed by a Nar∣cotick or a watry humor: certain reliques of which, being resolved into vapor, and thrust out from the company of the Spirits, do often sweat out, or drop into this Vacuum or empty space.

After this manner, it may be believed concerning the Ventricles of the Brain, or the empty space left within its plicature or folding together. But in truth, because this matter hath been very much controverted among Physicians of every Age, and the right decision of it seems to be of great moment, for the explicating the offices of the other parts of the Head; I will here compare together the reasons for and against this Opinion, that we may at length give our Judgment of this Opinion, what may be either true, or most likely.

CHAP. XII. It is inquired into, whether the serous Humors, heaped together within the Vacuity of the Brain, be sent out by the Pituitary Glandula and the Sieve-like Bone, or not?

SInce Experience testifies, that the Serum and excrementitious, I may justly say morbifick, and of∣tentimes deadly Humors, are found frequently within these Ventricles of the Brain; we ought to enquire more diligently concerning their passage in and out: and the rather, for that it is very much doubted by some concerning the use of these Dens, nor are there wanting those in this late Age, who have endeavoured to bring into vogue the ancient Opinion, though long since exploded, concerning the Spirits being begot in this place, and here exercised. I believe without doubting, for the reasons before alledged, that the Spirits are not here begotten, nor exercised. and no less certain is it made by Expe∣rience, that the serous Colluvies is here often gathered together. This therefore only remains, that we should see from whence, and how this flows hither, and then by what ways of Excretion the same should be carried out.

As to the first, it is exceeding probable, that the serous Latex, which is the Vehicle of the Spirits newly produced, and is introduced together with them into the Pores of the Brain, after it is grown stale, and being attenuated into Vapour, doth distil forth into this Cavern, and there at last grows in∣to a watry Humor: for otherwise what becomes of that Humor, or into what other Receptacle could it be derived? Besides this ordinary, and I believe assiduous heaping together of the serous Colluvies within the Ventricles of the Brain, certainly it may be believed, that this kind of serous Humor is distilled out of the Glandula's inserted in the Choroeidal infolding, being too much filled, into the Ventricles so called. I have often seen in a Dropsie the Glandula's of the Brain to be intumified, and like grains of Barley, burst∣ing with too much wet, to become flaccid or withered, so that they could not retain the serosities brought to them, but continually disposed them into the Cavity beneath. Truly in a Dropsie of the Brain these Ca∣vities or Ventricles are always seen to be full of water; the cause of which kind of distemper is, the blood being made more watry, puts off in its circulation a greater heap of Serum than the Veins can presently carry back, or the Glandula's are able to receive and retain. For indeed, that the Serum, redounding on every side from the Vessels, may the better slide into the Ventricles of the Brain, it is so ordered, that the g•…•…eater infoldings of the Vessels, with the inserted Glandula's, should be disposed near all the Ventricles of the Head: because, not only the infolding Choroeides is placed nigh the concourse of the three Ventricles in the Brain, but another infolding, and no less noted, (which we have above described) with greater Glandula's, is set behind the Cerebel nigh the fourth Ventricle, In all, as it seems, for that end such care is taken, that the watry part, coming from the blood, which is destinated either for the Brain or the Ce∣rebel, for that it is not fit for the procreating of Spirits, might run into these infoldings of the Vessels. But yet if a greater plenty of Serum be there laid up, than can be contained in them, or may be sent away outwardly, whatever is superfluous will slide into the Cavity underneath.

Hence it appears, from whence, and by what means the serous heap is gathered together within the Ventricles of the Brain: certainly to deny this going out is no other than to assert every ones Brain big with a Viper, which cannot be brought forth but by gnawing asunder the bowels of its parent. Who shall lightly consider the parts nigh the Ventricles, and their Fabricks, at first sight only would swear with the Ancients, that the excrements of the Brain were laid aside both Iower through the Tunnel into the Palate, and above or more forward through the mammillary Processes into the Nostrils: But if the structure of these parts be a little more diligently searched into, there is no body who presently will not easily think, that by neither of these ways the excretion of any humor can be made; for neither from the pituitary Glandula through the Wedge-like bone, nor from the mammillary Processes through the holes of the Sieve-like bone, is there any manifest aperture or opening to be perceived. But in very truth, we do suppose that the Brain is in some measure purged by Both these Emunctories, for that objection may be answered, That the translations of Humors in living Creatures are easily performed through pla∣ces that seem impervious or unpassable; for while the Pores and passages in all the parts of a living Crea∣ture are dilated by spirit and heat, they transmit the rain of the Serum as through the fine texture of a woolen Cloth. This plainly appears from Athritick distempers, in which the serous Latex creeps by degrees through the nervous bodies, and passing through very small spaces, makes a falling down of humors some∣times upon these parts, and sometimes upon others; so that it is obvious, that the Membranes and nervous Processes drink in the serous humors like Sponges, and then by a light compression render them by heaps, as is manifest in the Tooth-ach; for as often as a Bodkin or Instrument is put up into a hollow Tooth, clear water will come out plentifully. Indeed, in the body of a living Creature the passages of humors are not only made through open passages and chanels; but the thinner and more watry Latex creeps through the solid and smooth bodies of the Nerves, as also the Fibres and the Membranes, as through the holes of a Filtre, and so is transferred through imperceptible straits from place to place. I sometime knew in the Impostume of the Lungs the humor to have been derived through the Membranes growing to the Pleura from the bag into an Issue made in the side, and so the spitting ceasing, the Disease that seemed otherwise incurable, was healed by such a way of Evacuation. Why in like manner may we not suppose the serous humors falling down from the Ventricles of the Brain into the pituitary Glandula, and the mammillary Processes to be carried away through the Nerves or Membranes passing through here or there?

Concerning the Tunnel, the thing is probable enough; because the position and structure of this seem to shew, that some humor is carried out of the Ventricles of the Brain towards the pituitary Glandula. For this part is so constituted, that a falling down of the humors may be made from every angle and recess of the interior Brain and its Appendix into its aperture or opening. And as in several Animals, the figure and site of the Ventricles vary very much, (as we have already shewn) yet in every one of them all the Ventricles of the Head, whatsoever they be, have their openings gaping towards the Tunnel. But that this Kernel or Glandula, to which the passage of the Tunnel is inserted, receives and carries out the serous humors, seems also to appear from hence; because it admits, not only those falling from the Brain into its Pores, but also those secreted from the blood ascending into the Brain: For that in ma∣ny four-footed beasts, certain Vessels are inserted to this Glandula from either Carotidick Artery, which intimately enters its substance: a sign of which is, that Ink being injected into the Trunk of either Artery, dyes with a black colour the wonderful Net, if it be there, and oftner the interior substance of this Glan∣dula: whence it may be argued, that the office of this Glandula is to receive the superfluous serosities; and it receives not only those sent away in the return from the Brain, but sometimes preoccupies or pre∣vents them, and is wont to derive them from the blood before it is carried to the Brain. And therefore this Glandula is very small, if the superfluities of the Serum be derived to it only from the Brain; but great∣er, if they come to it also from the blood, to wit, as it executes either one or a double office, as we have al∣ready shewn at large.

But as to what respects the way of passing through, to wit, by which the humors deposited in this Glan∣dula, are carried out, the vulgar Opinion is, that they do come away through the holes of the bone be∣neath into the Palate: wherefore in those kind of Animals, who have the wonderful Net, and many of its shoots enter this Glandula, more holes are made in the underlying Bone. Further, if you take away the ditch or gutter of the Wedge-like bone, or the seat of this Glandula cut off from the Skull, and pour wa∣ter upon its holes being made bare from the Membrane, it passing presently through the substance of the whole bone, will suddenly still forth through other holes lying open in the sides of the bone. Yet this Experiment concludes nothing for the Opinion proposed: because these holes are wholly wanting in some Creatures, and very much in an humane Skull; in those who have them, as in a Calf, es∣pecially it is observed, that the same are filled by some hollow Vessels; into which, if a black liquor be cast by a Syringe, that passing through the substance of the bone, will go into many other Vessels ly∣ing under the bone, and at length into the Trunk of the Jugular Vein; which certainly is a sign that the humors are not carried from hence into the Palate. But as to the Vessels which cover over the holes of the bone, and which more abundantly lye under the same, they seem to be either Veins or Lym∣phaeducts.

But among these it is lawful to conjecture, the chief means of Excretion, whereby the serous humors, laid up in the pituitary Kernel, may be carried out; to wit, that they are remanded back from it, as from most other Glandula's or Kernels, into the mass of blood. In a C•…•…lf the thing lies open

to ocular Inspection, nor is it to be doubted of other Animals, who have the admirable Net: because as the arterious branches, so also the veinous reach to this Glandula; which sup up not only the humors depo∣sited from the Arteries, but also those falling from the Ventricles of the Brain. Yea, it may be lawfully believed, that in a Man also, a Horse, and in other Creatures, who want the strange or wonderful Net, there are other Lymphaeducts or Water-carriers, or such kind of Vessels, as are seen in the head of a Calf, that most certainly carry the humors from this Glandula. We cannot so easily find out their footsteps, because, before these break out of their dens, the tracts of the Lymphaeducts, if there be any, would vanish. Nor can we find out these Vessels in all, as in a Calf, by injection; because the holes of the bone, by which, as by the leading of a thread, the injection arrives at, and dyes the Vessels, otherwise lying hid, are wanting in most. No doubt but time will render sufficiently manifest the reductions of the humors from the pituitary Glandula in other living Creatures: in the mean time, it may be lawfully suspected, for that the serosities in some are remanded from thence into the bloody mass, that in all it is done after the like or the same manner, although the ways of the passing do not yet sufficiently lye open.

As to the other Emunctory of the Brain, to wit, whereby the serous humors, laid aside from the Ven∣tricles of the Brain into the mammillary Processes, and thence are thought to be sent away through the holes of the Sieve-like bone▪ truly, concerning this way of Excretion, it is much more to be doubted, be∣cause these holes in the defunct being covered over and fully stuft, with the insertions of the Dura Ma∣ter and nervous Fibres, sent on either side from the mammillary Process, transmit nothing of humor, how clear soever it be. Further, there is nothing more certain, than that the serous humors are pressed out from the Glandula's and extremities of the Vessels ending within the Nostrils into their Caverns; so besides that 'tis scarce possible for the humors to descend thither from the Brain, it is not absolutely needful to suppose this sort of means of Excretion. But that we may reason a little farther concern∣ing these; if it may be lawful to argue from the provision, and from the effects of the parts, there is no reason but that I may probably believe, that some humors also do shower down from the Brain into the cavities of the Nostrils: for it being supposed, that the serous humor passes through, not only open chanels, but the more strict Pores and passages also of the Nerves, and creeping both through the Fibres and Membranes, as through the strainings or holes of a Filter or Strainer, is carried from place to place, (which it were easie to demonstrate) what should hinder but that the same sort of Latex may descend through the Fibres impacted in the holes of the straining bone? For although in dead creatures those parts seem to be impervious or unpassable, yet during the life of the Animal the passages and blind ways of the nervous bodies, being dilated by Spirit and Heat, most easily transmit a copious humor where with they are watered.

The Sieve-like Bone in divers Animals is varioufly perforated for the manifold necessity and difference of smelling. A Process from the Dura Mater and manifold nervous Fibres pass through every one of its holes, and besmear the inside of the Nostrils. But as the impressions of sensible things, or sensible Spe∣cies, continued as it were by the undulation or waving of the animal Spirits, ascend through the passages of these bodies stretched out from the Organ towards the Sensory; so the humidities watring the same bodies, for as much as sometimes they may be more superfluous than usual, may distil into the Nostrils through the same ways. For indeed such humors as are perpetually to be sent away from the brain, ought so copiously to be poured upon the Organs of Smelling, as we shall shew hereafter, when we shall speak particularly of the Smelling Nerves; in the mean time, that there is such a way of Excretion opening into the Nostrils, some observations, taken of sick people troubled with Cephalick diseases, do further perswade. I have known some very obnoxious to the Scotomy and Vertiginous distempers, who had great plenty of clear water that distilled forth about the end of the Fit; by which kind of Evacuation, as it were Critical, the Fit was wont to be ended. Not long since, a Virgin living in this City, was affli∣cted a long time with a most cruel Head-ach, and in the midst of her pain much and thin yellow Serum daily flowed out from her Nostrils: the last Winter this Excretion stopped for some time, and then the sick party growing worse in her Head, fell into cruel Convulsions, with a stupidity; and within three days dyed Apoplectical. Her Head being opened, that kind of yellow Latex overflowed the deeper tur∣nings and windings of the Brain, and its interior Cavity or Ventricles. I knew a Gentlewoman that was wont to be infested with a most cruel Head-ach, also with a Vertigo, and a frequent melting of the Animal Spirits, or Swooning away; who when she began to be better after a grievous Fit, felt at first a creeping motion in the top of her Brain, as it were the sliding down of water: then that motion passing a little more forwards and downwards, at length many drops of clear water distilled from her Nostrils. This Symptom she used to have so ordinarily, that the sick Gentlewoman did not doubt but that this wa∣ter stilled out from the Brain it self. I could here bring many other reasons, which might seem to per∣swade, that the Ventricles of the Brain, or the Cavity made by the complicature or folding up of its bor∣der, is a mere sink of the excrementitious Humor; and that the humors there congested, are purged out by the Nose and Palate: But it is time for us to hasten to other matters, and to pass from the Brain, properly so called, to its Appendix, viz. the oblong Marrow and the Cerebel.

CHAP. XIII. The Actions and Uses of the oblong Marrow, and some of its Parts are unfolded.

WE will pass now from the Brain to the explication of its Trunk, to which both it and the Cerebel do grow like Mushrooms or large Excrescences. This part is commonly called the Oblong Marrow; under which name we comprehend all that substance which reaches from the inmost Cavity of the callous body, and con•…•…uncture in the Basis of the Head, to the hole of the hinder part of the Head; where the same substance, being yet farther continued, ends in the spinal Marrow. The superficies of the oblong Marrow, though it be made unequal with some protuberances and processes, yet it is not variegated or garnished with any turnings about, and involutions, as it is in the Brain and Cerebel; neither is its exterior and cortical substance, or of an Ash-colour, and the interior, medullar or marrowy and white; but all its frame or substance is in a sort marrowy or me∣dullous: nor does it however appear pure and bright, but much darkened with fibres and hairs variously stretched forth, and diversly going out. To wit, its fibres being figured in various places, after a diverse man∣ner, in some places they are found chamfered, and as it were beamy, in others direct or stretched out at length, and in other places again circular.

The Figure of this is forked, and as it were like the Poets Parnassus, seems like the letter Y: for its shanks arising more forward from either Hemisphere of the Brain, and inclining one to another grow to∣gether near the centre of the Skull into one and the same Trunk; which not withstanding, a line being brought through the midst, seems to be made as it were out of two stalks, and those to be distinguished in its whole process.

The oblong Marrow seems to be a broad or high Road, into which the Animal Spirits perpetually flow from their double Fountain, to wit, the Brain and the Cerebel, to be derived from thence into all the ner∣vous parts of the whole Body; which Spirits, whilst they are orderly disposed in this common passage, as it were by series and orders, carry a twofold aspect; to wit, they are directed either outward towards the Nerves, when they exert the loco-motive Faculty, or they look inward towards their Fountains, when the acts of sense, or rather the apprehensions of sensible things are performed.

Within this open way, a more large and greatly open path leads straight to the spinal Marrow, through which the Spirits flow forth to the Nerves, the Executors of spontaneous motion in most Members. In the mean time, out of the same tract of the oblong Marrow, lesser paths are carried outwardly, here and there, by particular Nerves, arising from the same, within the Skull. Also besides, many diverting pla∣ces, viz. various processes and protuberances grow to this medullary Trunk, into which, the Spirits desti∣nated to some peculiar offices, go apart: lest that all the Spirits travellinng this way, and that way in the same path, should meet one the other and disturb one anothers offices.

Whilst after this manner, for the performing the acts of Motion and Sense, we suppose the Animal Spirits to be expatiated within the oblong Marrow; we affirm, that they are not there begotten, but only exetcised. For indeed, they being created only in the Brain and Cerebel, as they proceed from this or that, they perform the offices, either of a merely involuntary Function, or else of a spontaneous, as shall be shew∣ed more largely hererster.

But that we may unfold here all things which belong to the oblong Marrow, I shall mete it forth from its first coming out to the end of its race, and handle its several Stadia, diverting places, and cross ways. Where the callous Body is thought to end, the oblong Marrow begins, to wit, when the medullar sub∣stance of the Brain is thickest nigh the bosses or knobs of either Hemisphere, a body of a whitish colour and somewhat darkned or obscured, and streaked like Ivory, is joyned to that Marrow on both sides. These two bodies are the extremities or tops of the shanks of the oblong Marrow; between which and the Brain there are nigh and very immediate commerces. Either of these seems as it were a Cylinder rolled about into an Orb, which nevertheless constitutes the top of either shank, not spherical, but oval, and something bent downward in the hinder part. A more large portion of its superficies is joyned to the medullar substance of the Brain; but yet some part of it, being free from the cohesion with the Brain, shews it self apart, and makes that protuberance shewing it self in either lateral Ventricle. These bo∣dies, if they should be dissected along through the middle, appear marked, with medullar streaks, as it were rays or beams; which sort of chamferings or streaks have a double aspect or tendency; to wit, some descend from the top of this body, as if they were tracts from the Brain into the oblong Mar∣row; and others ascend from the lower part, and meet the aforesaid, as if they were paths of the Spirits from the oblong Marrow into the Brain. And it is worth observation, that in the whole Head besides there is no part found chamfered or streaked after the like manner.

If the use of these be inquired into, this presently occurs, that these bodies, placed between the Brain and its Appendix, are the great and common diverting places of either; to wit, which receive whatso∣ever impulses or forces of the Animal Spirits are sent from either, and communicate them presently to the other: Or that I may speak more plainly, this part is the common Sensory, to wit, as Aristotle saith, 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉, the first Sensory that receives the strokes of all sensible things, dilated from the Nerves of every Organ, and so causes the perception of every sense; which kind of strokes of sensible things, when from hence they are passed further into the Brain, presently Imagination succeeds the Sense: and further, these bodies, as they receive the forces of all the Senses, so also the first instincts of spontaneous local motions. To wit, as often as the Appetite discerns any thing to be done, presently the reciprocal tendencies of the Animal Spirits, that is, from the Brain into these parts, are disposed here to act the conceptions of motions coming from any part or member. For here, as in a most fa∣mous Mart, the animal Spirits, preparing for the performance of the thing willed, are directed into ap∣propriate Nerves. That it is so, it appears, because every influence from the Brain into the nervous stock, and on the contrary, from this into that, and the mutual commerce of the animal Spirits, must of necessity pass through these bodies, Wherefore all the Nerves, also those which belong to the more in∣ward Organs of the Senses, arise behind these chamfered bodies. For the Optick and smelling Nerves creep through the superficies of the Brain by a long passage and windings about, that they might be in∣serted below this part of the oblong Marrow.

For indeed, the Species of sensible things, received by those Nerves, might more immediately be car∣ried to the middle of the Brain, unless that they ought first to be staid at this Sensory. Further, we may lawfully conjecture, that these parts perform the aforesaid office from their chamfered, and as it were bea∣my contexture: For as those chamfering with which these bodies are marked, (as we but now intima∣ted) are of a double kind, to wit, some descending, which look from the Brain towards the oblong Mar∣row: and others ascending, which are carried distinctly from this towards that, it may be lawfully con∣cluded, that in these carried upwards, the impressions of sensible things are perceived, and in those tend∣ing downwards are performed the Instincts of Motions.

Further, that these bodies, as was said, perform the offices of the first Sensory, besides the fabrick of their parts, and the Analogy to be collected thence of their use, it seems yet more certainly to appear from some Observations concerning these chamfered bodies, after what manner they are affected in Pa∣ralytick diseases. For as often as I have opened the bodies of those who dyed of a long Palsie, and most grievous resolution of the Nerves, I always found these bodies less firm than others in the Brain, disco∣loured like filth or dirt, and many chamferings obliterated. Further, in Whelps newly littered, that want their sight, and hardly perform the other faculties of motion and sense, these streaks or chamferings, being scarce wholly formed, appear only rude.

The chamfered Bodies, inclining one to another near their blunt and greater angles, are almost con∣tiguous; but that the Trunk of the Fornix intervenes with its twosold Root: yet in that place where the two Roots of the Fornix, being sent straight down, are inserted into the callous body, a transverse me∣dullar process, like a great Nerve, stretched from one chamfered body to the other, as it were joyns the same, and makes them to communicate one with the other. Certainly, this joyned together of the cham∣fered bodies is made, that their actions and passions may not be double: but though the species of the sensible object or conceptions of the motions to be performed, coming from the Brain or Sensory being double, are carried also double to the first Sensory; yet for as much as either substanc or frame of this, communicates with the other, every impression coming this or that way, becomes still one and the same. For it may be observed, in the whole Head, that though almost all things are double, yet each of them communicate among themselves, either by a contiguity, or by processes sent forth. And so as by the du∣plication of it, care is taken against the absolute privation or defect of the act, so the joyning together of its duplicature provides against the empty or confuse multiplication of the same species.

After this manner, the chamfered bodies in Man and four-footed Beasts are constantly found of the same species or form, and in every one of them, figured after the same manner; and are as it were the Joynts that joyn the brain to the shanks of the oblong Marrow. But we have already shewn, that in Fowls and Fishes, whose brains being alike, differ from those of men and four-footed beasts, the thing is somewhat otherwise: For in Fowls the callous body is wanting to the brain; but what serves instead of it, is found in the oblong Marrow, to wit, two little Ventricles shew themselves nigh the chambers of the Optick Nerves, which are arched or chamber'd with a whitish substance, such as the callous body is in man or four-footed beasts. Then on the contrary, the chamfered bodies, or the parts which serve in their stead, in Fowls, are not a portion of the oblong Marrow after the usual manner, but are entred into the Brain it self. For near the fissure of the Brain, two Membranes being marked with medullar chamferings, both distinguish either Hemisphere of the Brain, and cover over its Ventricles. The streaks or rays of either Membrane descend, and being concentred about the Basis of the Brain, go together into a medullary process, which is inserted on both sides to the oblong Marrow. So these parts, viz. the cal∣lous body, in which the animal Spirits are expanded, and the chamfered bodies, in which their passing to and fro is instituted, seem to be transposed in the head of Fowls. The reason whereof, (as I else∣where hinted) unless I be deceived, is this: because these Animals are of less excellency in imagination and Memory than four-footed Beasts; yea also, for that the sense and motion of them are their chief

Faculties: therefore for the exercises of these to be performed with a greater expansion of Spirits, the callous body is transferred into the oblong Marrow, and in its place the chamfered bodies are removed into the Brain.

About the lower end of either chamfered body the smelling Nerves are inserted. For you may take no∣tice, that the mammillary Processes, a little more obscure in man, but much more conspicuous in brute Animals, who are endued with a more remarkable sense of smelling, do pass into firm and plainly whitish bodies of Nerves, which being dilated or brought nigh the lateral turnings and windings of the Brain, are implanted into the oblong Marrow on either side about the lower angle of either Ventricle be∣hind the chamfered bodies; yet so, that the Tube or Pipe of either Nerve may open into the Cavity of the Ventricle, as we before shewed. After this manner these Nerves are carried by a long journey from the fore-part of the Brain, that they may bring the sensible species to the chamfered body, as to the com∣mon Sensory, first and rather than to the Brain. But we shall speak of the smelling Nerves more particu∣larly hereafter.

Where these chamfered Bodies end from either fide, a marrowy substance succeeds, which being some∣what of a darkish colour going forward for some space, is distinguished by a peculiar bending forward from the other contiguous parts. This Galen (perhaps not improperly) calls the Chambers of the Optick Nerves; for in this place the Optick Nerves shewing themselves from the highest region of either side, being carried downward with a certain compass, are united about the Tunnel. Then being divided again, and carried a little further, enter the Skull, going straight forward to either Sensory. The grow∣ing together of these Nerves, and their being again separated, seems to be ordained for this end, that the visible species, received from either Eye, might appear still the same, and not double; for this conjuncti∣on of the twosold Organ frames the double image into one; which once united, when afterwards it is carried to either side of the common Sensory, for that it is on both sides alike, appears still the same. If at any time, through drunkenness, or a distortion of the Eyes, the object appears double, and two Lights upon a Table, it is because the image of the same thing is received after a different manner by one Eye than the other, for that reason the objects are represented like two distinct things. For that this Eye is di∣storted after one manner, and that after another, the same Species, coming to either Pupil by a diverse angle of incidence, appears diverse or double. There is another reason of the coalition of the Optick Nerves, to wit, that one Eye being hurt, all the visible Animal Spirits might be bestowed on the other. Further, for that these Nerves are carried with a long passage, their uniting helps to their mutual strength and support.

Whereas the Optick Nerves arise here from the oblong Marrow, all or its most intimate substance is not bestowed upon them; but these Nerves are inserted into the medullar Trunk, as branches of a Tree to the stock, that so they may receive by that means the influence of the Spirits, and by this way transmit the Species of visible Things. In the mean time, this more inward substance of the oblong Marrow is the common passage both to the Eyes and to the other nervous System arising more backward: through which, by the going and returning to and fro of the animal Spirits, the impulses of sensible things, and the instincts of Motions between the Brain and the other nervous parts, which depend upon it, are per∣formed. Forasmuch as the smelling and seeing Nerves arise so near the chamfered bodies, the reason hence is plain, why odors or the objects of the sense of smelling so strike the Brain it self, and immedi∣ately affect it; also why there is so exceeding swift a communication between Sight and Imagination.

Concerning the Optick Nerves in a Man, (which also in some measure is after the same manner in other living Creatures) we shall advertise you, that when they, after their uniting or mixing together, being presently again separated, do go out of the Skull, the sanguiserous Vessels going out of the Skull with them, and following either Nerve even to the Basis of the Eye, are knit into the Trunk of either There is a noted shoot of the Artery destinated to this office, carried from the anterior branches of the Carotides. Hence, as I suppose, a reason may be given, wherefore, when by drinking or more plentiful eating, a sleepiness is caused, presently a great heaviness, and as it were an oppression, is felt about the Eyes. For when the blood, very much boiling up, fills above measure the Vessels watering the Brain, and by distending them, obstructs the Pores of the Brain, those Nerves also from the blood in like man∣ner boiling up within the Optick Vessels, are pressed together in their whole passage.

In Fowls and Fishes this chamber of the Optick Nerves, bunching out with a great bulk, is not much less than the Brain it self; for, as we but now intimated, what is instead of the callous body is placed here; and in this place the Animal Spirits seem to have their chief Mart or Empory in a most large me∣dullar chamber, or the Sphere of their Expansion. And so, when from hence the Animal Spirits are derived from so full and plentiful a Store-hose, it is for that reason Fowls are furnished with so curious an Eye, and with so highly perspicacious and acute a sight. And the same perhaps may hold concerning Fishes, if that we consider the sight in these is performed in a thicker Medium, and often double.

In some Animals, in the midst of these chambers of either Optick Nerve, the shanks of the oblong Marrow a little opening, leave a chink or aperture, which receiving the serosities coming from every re∣gion of the Brain and its Appendix, sends them through the Tunnel into the pituitary Glandula.

There is no need that we should discourse much here of the Tunnel and the pituitary Glandula, be∣cause, already speaking of the Ventricles of the Brain, or the empty space left within its plicature, we fell occasionally on the consideration of both these: where we shewed, that the serous humors, which were

wont to be heaped together within many places of the Brain and of its Appendix, do all slide down on every side from each angle and recess of it into the steep opening of the Tunnel; and so there is a ne∣cessity that they should be poured out by it into the pituitary Glandula. Further, it is manifest, that this Glandula, in some Animals, is charged with a double office; to wit, as it receives the serosities sent from above from the Brain, so also it separates the humors from the blood brought to the same from the won∣derful Net by the Arteries, and prepossessing them, imbibes them before their ingress to the Brain. Where∣fore this part is furnished with a substance of a double kind, viz. one reddish, more thin, and interwoven with Blood-carrying Vessels, which constitutes either side of it; and the other more white placed in the middle, to which the Tunnel is inserted.

But having shewn, that this Glandula receives the humors so brought by a double Tribute, we did di∣ligently inquire concerning the ways and means whereby they are at length carried away from thence, and as it appears by an Experiment, that there is a passage open from this Glandula into the Vessels ly∣ing underneath the bone, and from thence into the Jugular Veins, we affirmed, that 'twas most likely, that the humors to be carried away from this Glandula, (after the manner of others) may be reduced at last into the bloody mass. I shall not add any more concerning these things, but proceed to the other parts of the oblong Marrow. But that, what hath been said, concerning the shanks of the oblong Marrow, and their tops, viz. the chamfered bodies, may be the better understood, it will seem to the purpose that we represent the Images of all these in the following Figure.

The Eighth Figure.

REpresents the oblong Marrow taken out of the Head of a Sheep with the Brain cut off and remov∣ed, and with the Cerebel and one streaked Body cut in two in the middle, and other things chiefly belonging to the medullar Trunk.

• AA. The chamfered Body cut in two in the midst, that its marrowy chamferings may appear.
• B. The other chamfered Body whole covered with the Choroeidal Infolding with the extreme portion of the cal∣lous Body CC. sticking to the same.
• CC. The brim or extremity of the callous Body cleaving to the chamfered Body.
• D. The Basis of the Fornix.
• E. The right wing of the Chorotidal Infolding.
• F. The passage of the Veins being stretched out from the fourth bosom, which being presently forked, constitutes the veinous portion of either wing of the Choroeidal Infolding; under the beginning of this passage, very much beset with Fibres and sanguiferous Vessels, the Pineal Glandula lyes hid.
• G. The hole or chink leading to the Tunnel.
• HH. The chambers of the Optick Nerves.
• II. The medullary processes, or the ways of passage which lead from the medullar stock into the orbicular Pro∣tuberances.
• KK. The Buttock-form orbicular Protuberances.
• LL. The lesser Protuberances called Testes.
• M. The meeting together of the Processes ascending obliquely from the Testes into the Cerebel.
• N. The hole of the lower Ventricle lying under the orbicular Protuberances.
• OO. •…•…he pathetick Nerves of the Eyes.
• PP. The medullary Processes stretched out from the Testes into the Cerebel.
• QQ. Other medullar Processes, which being sent from the Cerebel towards the oblong Marrow, compass about its stock, and constitute the annular or ringy Protuberance.
• RR. The lowest or third Processes of the Cere•…•…el, which being inserted to the medullar Trunk, become additio∣nal cords or strings of it.
• SS. The medullar Ramifications or Branching of the Cerebel.
• TT. The middle marrows of either Cerebel in which its three medullary Processes, constituting either little foot of it, grow together.
• V. The Ditch constituting the fourth Ventricle in the medullar Trunk.
• X. The extremity of the oblong Marrow about to end in the Spinal.

[illustration]

Fig. VIII.

II. p. 86

CHAP. XIV. Of the Uses of the Pineal Glandula and the Choroeidal Infolding; also of the orbicular Prominences which are commonly called Nates and Testes; and other Parts which seem to be dependences of them.

BElow the Chambers of the Optick Nerves in a common Valley which lyes between the tops of these and the Buttock-form Prominences, is placed the Pineal Glandula or Kernel in form of a Pine-apple, called also Conarium; this is not only found in Man and four-footed Beasts, but Fowls and Fishes also are enduced with the same. Wherefore, although from hence it may be concluded, that this is of necessary use; yet we can scarce believe this to be the seat of the Soul, or its chief Faculties do arise from it; because Animals, which seem to be almost quite destitute of Imagination, Memory, and other superior Powers of the Soul, have this Glandula or Kernel large and fair enough.

It is observed in all Animals of every kind and form, that to this Glandula, always placed nigh the holes or passages, open to the Tunnel, the Choroeidal Infolding is continually joyned; yea this infold∣ing (seeming to hang from the Pineal Kernel sustaining its middle Process, as it were by a nail or hasp, from thence) is divided into two wings stretching out on either side upon the shanks of the oblong mar∣row, Wherefore we may justly suspect, that this Glandula is chiefly made for the sake of this infolding; and that the office of it is no other than of other Kernels, which are placed nigh the concourse of the sanguiferous Vessels: to wit, that it may receive and retain within it the serous humors deposited from the arterious blood, till the Veins being emptied, may sup them back, or the Lymphaeducts (if there be any there) may convey them outwardly. For it is observed, that the Choroeidal infolding is beset with very many lesser Glandula's or Kernels, and every where interwoven with them, which imbibe the Serum se∣creted from the blood, in the smaller Vessels; therefore for this very same office, where all the Vessels concur, this Kernel is placed, of a bigger bulk, that it might be able to receive and contain the serosities there plentifully deposited. Moreover, it is of no small moment, that this Glandula sustains and keeps du∣ly stretched out the Choroeidal infolding otherwise hanging loose, and apt to fall down into it self, or at least to slide out of its proper place. Wherefore I have often taken notice in the Dropsie of the Brain, that this Glandula being loosned at the roots by too much moisture, and often broken off, and removed from its place, the Choroeidal infolding hath slid together from its proper expansion, and slip'd down lower, and also suffered its Vessels to be folded together disorderly.

From these things thus premised concerning the Pineal Glandula, it will not be difficult to assign also the use of the Choroeidol infolding Concerning which there will be little need to refel that Opinion of the com∣mon sort, which asserts, That the animal Spirits, to be bestowed upon the whole Brain, are begot in this infolding: because the Vessels of this instil nothing to the substance of the Brain or its Appendix, for that they are no where inserted to it; but it was before shewn, that the Ventricles of the Brain, or the Ca∣vity in which these same Vessels are hung, do not at all contain the Spirits; which further appears more plain, because in Cephalick diseases those Ventricles are filled with water, and the continuity of the in∣folding is dissolved by too much moisture, when in the mean time the sick are indifferently strong in the exercise of the animal Faculties.

But indeed we suppose, that this infolding serves for a twofold office: viz. First, that the more watry part of the blood, destinated for the Brain, might be sent away into its Vessels, to the end, that the re∣maining portion of the bloody Latex might become more pure and free from dregs to be distilled forth in∣to Spirits; even as is wont to be done in a Chymical Distillation, to wit, when there is a peculiar Receiver fitted for the receiving of the Phlegm by it self, more sincere, pure, and subtil Spirits are instilled into the other more noted Receiver. The more watry blood entring the arterious Vessels of this infolding, being carried from them into the Veins, is remanded back towards the Heart. In the mean time, lest the Serum, too much redounding, and boiling up in these Vessels, might hinder circulation, its superfluities are re∣ceived for some time both by the lesser Glandula's thickly inserted, and also by the pineal Kernel.

The other and no less noted use of this Infolding, is to conserve the heat of the blood boiling within the complications of the Vessels, and as it were circulating about, being excited as from a fire-place within the infolding of the Brain. For though the Pia Mater need not implant thick shoots of Vessels in the cal∣lous Body and inward Marrows of the Brain, for that they are rather dedicated to the Exercise than to the Generation of the animal Spirits; yet that the heat requisite for the circulation of the Spirit, might be kept constantly in that place, this infolding is hung upon the whole neighbourhood. For as the blood, aggested or heaped together within the Cavities of the Bosoms, is instead of an

hot Bath, whereby the animal Spirits are distilled plentifully into the outmost and cortical part of the brain; so the blood contained within the small Vessels of this infolding, seems to be in the place of a lesser and more temperate Bath, whereby the same Spirits might be fitly circulated in the more inward and medullar substance.

Lastly, Another reason may also be given, why the Choroeidal infolding is found always within the Ventricles or Cavity of the Brain, made by its infolding, and after what manner soever figur'd; to wit, that another sort of commodity might result from thence; that when the Vessels of that infolding, carry∣ing too watry blood, lay aside more Serum than the Glandula's are able to receive or contain, whas is su∣perfluous might slide down opportunely into the underlying Cavity, as into a Sink. Wherefore the Pi∣neal Glandula, though set in a more eminent place, is however placed always near the hole or passage that lyes open towards the Tunnel in every Brain.

Next to the Pineal Kernel are found in the upper superficies of the oblong Marrow certain noted Pro∣minences, which are commonly called Nates and Testes. These being placed naar together, do consti∣tute as it were four Mole-hills, which yet are joyned one to another by certain processes. Beneath these Mole-hills, or rather between the joyning of them and the runk of the oblong Marrow, placed underneath, a narrow and long Cavity or Den is left, which by some Anatomists is called the fourth Ventricle; but according to others later, who place the fourth Ventricle under the Cerebel, this Cavity is affirmed to be a passage to it.

The hinder extremity of this Den ends nigh the beginning of the fourth Ventricle; the more fore-ex∣tremity of it opens before the former Mole-hils or little bulkings out, called Nates. From the midst of this Cavity or narrow Den a passage goes straight to the Tunnel. It is very much controverted among Anatomists concerning the site of these parts, and of their dependency on one another, and of other parts, and of their use: Concerning which this is first to be noted, as we hinted above, that these four Protube∣rances are far greater in some brute Animals than in a Man, as in a Sheep, Calf, Goat, and the like; also in a found dry, and old Head they are more conspicuous, and their processes, joynings and habitudes may be more easily noted than in a younger, moist, or otherwise sickly brain. Indeed the use of these (unless my conjecture deceives me) seems far more noble, than that they should deserve those vile names of Nates and Testers, Buttocks and Testicles.

Notwithstanding, to what office these parts were designed, neither have the ancient Anatomists deli∣vered, nor will it, by the help of Reason, be easie to guess for certain. We have already shewn, that these aforesaid Prominences ought not to be taken for the two shanks either of the Brain or Cerebel bending back one towards another, and so growing together into the oblong Marrow. For although from this supposition a very neat Hypothesis may be made for the oeconomy of the animal Function, to wit, by af∣firming that these double shanks, on either side, were so many distinct ways of passage through which the animal Spirits, for the performing of motions, flowed from the Brain and Cerebel into the oblong Mar∣row, and returned thence from this into those for the performing the acts of the Senses: yet from our Method of Dissecting it plainly appears, that the brain is not fixed to the oblong Marrow nigh this place, but far above it; so that indeed the anterior Prominences, unless mediately only, viz. by the chamfered bodies, receive not any portion of the medullar stock, or any influence from the brain, nor can have any dependency from it. Besides, if the Protuberances called Nates were shanks of the brain, why should the same be in man, (he having got the greatest brain, the least) or at least lesser than in most other living Creatures? Then between the Prominences called Testes and the Cerebel, although there happens a cer∣tain communication; yet it seems that there lyes open a passage from those little lumps into the Cere∣bel, and not from this, through them into the oblong Marrow. For out of these aforesaid Prominences a medullar Process ascends obliquely one either side into the Cerebel, by whose passage the animal Spirits, tending frome one stage to the other, cause a mutual commerce between those parts and the Cerebel: But indeed the Processes which lead from the Cerebel into the oblong Marrow, and carry to it its influen∣ces, being distinct from the former, stand somewhat lower, as shall be more clearly shewn hereafter, when we shall speak of the Cerebel.

But in the mean time, concerning the offices and uses to which the aforesaid Protuberances serve, we shall make this conjecture. The animal Spirits perpetually flow out and leap back again from the foun∣tain the brain into the oblong marrow, so that there may be had a constant commerce between the brain and many organs of sense and spontaneous motion: from which those parts are entertained which per∣form their actions, not at the beck of the Appetite, but either by the instinct of Nature, or the blind im∣pulse of the Passions; for such receive wholly their influences from the Cerebel, as afterwards shall be more fully shewed. Whilst therefore the Spirits, flowing from the brain, abound in the oblong marrow, it is fit that some of them should be carried from thence into the Cerebel: (for what uses this ought to be done, shall be told by and by) wherefore from either side of the oblong marrow a Protuberance grows forth, into which indeed the Spirits designed for the Cerebel, may go apart from the common pas∣sage of the oblong marrow; and these Prominences are the former, which are commonly called Nates, and as we have said, are far greater in most brute Animals than in Man (the reason of which shall be declared anon.) The other hinder Protuberances, commonly called Testes, grow to these former, and are only certain Epiphyses or Excrescences of them, as it were the heads of the medullary Processes, which are from thence carried by an oblique ascent into the Cerebel; for when the animal Spirits

ascend from the former Prominences into the Cerebel, they enter these latter first, as it were the more large beginnings or entrances of their passage, from whence they go forward by the passage of the medul∣lar Processes into the Cerebel.

Besides we may take notice, that when the animal Spirits are carried out of the oblong marrow into the greater natiform Prominences to be derived towards the Cerebel, they, according to their custom, (as often as they tend towards the common Sensory from a double Organ of any Faculty) ought to be con∣founded and mingled together before they enter the Cerebel: wherefore both the first Prominences, and also the second growing to them are joyned together with certain Processes like wings reaching one ano∣ther; which connexion indeed of them, because it ought to be distinguished every where from the me∣dullar Trunk lying under it, hence, from the separation or empty space that comes between the oblong marrow and the growing together of the Prominences, that cavity arises, which is by some called the fourth Ventricle, and by others the passage to it.

If it be yet farther inquired, to what end the animal Spirits are carried by this by-passage from the com∣mon passage of the oblong marrow into the Cerebel, and thence back again; I say, that this is done for a twofold respect, viz. both that the Passions or Affections of the sensitive Soul, begun from the brain, may be transmitted to the Praecordia and Viscera; then secondly, that the natural Instincts, excited in the Praecordia and Viscera, might be communicated to the brain. These reciprocal commerces which are had between the Brain and the Organs of involuntary Functions, ought to be instituted or performed by this private passage, lest otherwise the exercises of these involuntary Faculties should very much di∣sturb the acts of the outward Senses, or the intentions of spontaneous motions.

As to the first, it is observed, that by every passion of the sensitive Soul, as srom Anger, Sadness, Plea∣sure, and other Affections, the Praecordia are disturbed, whether we will or no; which variously dilate or constrain themselves, and so stir up in the blood divers fluctuations. Moreover, from this kind of force of the Passions the countenance or the aspects of the Face are wont to be altered and distorted after various ways. The reason of all these seems to be, because when the animal Spirits, existing within the Brain, are moved according to the Idea of the conceived Passion, the other Spirits also flowing within these diverting places, being in like manner moved, affect the Cerebel, and that coming between, the ori∣ginal of the Nerves, serving to the Praecordia, Viscera, and Muscles of the Face, and so the parts to which those Nerves are distributed, are also stirred up or provoked into motions answerable to the same passion.

But the aforesaid Prominences and their dependences serve no less also for the conveying of the im∣pressions of natural Instincts to the Brain, that from thence the Appetite and local motions might pre∣sently be retorted; by which all the exigencies or wants perceived by the Praecordia or Viscera might be supplied. When in a young one newly born the stomach crys out for hunger, the Instinct of this is carried by the passage of the Nerves to the Cerebel, and from thence by the medullar Processes to these Protube∣rances; and the Spirits there inhabiting, form the Idea of the Impression, and carry it to the brain, wherein presently, without any previous knowledge or experience, such kind of conceptions of the Soul are stirred up, that every little living Creature presently seeks out the Mothers breasts and sucks.

But it may be objected, it does not seem of necessity we should suppose these kind of acts of the Passi∣ons and Instincts to be made apart in this by-place, for why are not the commerces of the animal Spi∣rits ordained by the influence from the Brain into the Nerves leading to the Praecordia, and so back again through the common passage of the oblong Marrow? But to that it may be readily answered, That this re∣ciprocal motion of the Spirits ought to be made through the middle region of the Cerebel, from one stage to another for the exercise of these Faculties: And therefore, (since that all manner of communication be∣tween the Brain and Cerebel is performed by these Prominences) there should also be had a passage by the same way between this and the Organs of the Functions merely natural. Besides, if the rage or furious mo∣tions of the Passions and Instincts should be carried in the same path in which the forces of sensible things are carried, their acts might be greatly confounded by the mutual meeting or gathering together of the animal Spirits. But this kind of Hypothesis concerning the Acts and Progress of the Passions and natural Instincts, shall be made more clear afterwards, when we design the Actions and Uses of the Cere∣bel, and of the other parts, which in like manner seem to be destinated to the same offices with these Protuberances.

In the mean time, what we have affirmed, that the latter Prominences are only Additionals or Excre∣scences of the former, will clearly appear to any one beholding them. But this, as we have already hint∣ed, is seen without Controversie in the brains of a Calf, a Sheep, and some other four-footed beasts; where, when the Nates are signally great, the Testes grow to the same in a very small bulk. Further, that the medullary Processes lead from these into the Cerebel, and convey the animal Spirits by this by-path, is so manifest, that none who hath carefully beheld these parts, can be able any further to hesitate or be doubtful of it. For indeed the little hairs or fibres wherewith these processes, ascending into the Cerebel, are marked, are otherwise figured and placed than those which are beheld in the neighbouring process descending from the Cerebel towards the oblong Marrow.

Moreover, either pair of Prominences do not only communicate among themselves mutually by their stretched out wings, but also another medullar Process, going cross-wise, knits together the aforesaid Processes stretched out from thence into the Cerebel; and from this joyning together of them two small Nevres are produced, which bending down on either side, and being carried forward, enter the Dura Mater, and so go straight through it, till having reached to the moving Nerves of the Eyes, they go forth of the Skull at the same hole with them, going forward, straight to the Throchlear Muscle of the Eye. Concerning these little Nerves it is observed, that when many others proceed from the sides or the Basis of the oblong Marrow, these arise from the aforesaid Prominences in the bunching forth at the top. The reason of which, if I be not mistaken is this: We have affirmed, that these Prominences do re∣ceive and communicate to the Brain the natural instinct delivered from the Heart and Bowels to the Cere∣bel; and on the other side, or back again, do transfer towards the Praecordia, by the mediation of the Cerebel, the forces of the Passions or Affections received from the Brain; but in either action the motion of the Eyes is affected with a certain manifest Sympathy. For if pain, want, or any other signal trouble afflicts the Viscera or the Praecordia, a dejected and cast down aspect of the Eyes will declare the sense of its trouble: when on the contrary, in Joy, or any pleasant Affection of the Praecordia or Viscera, the Eyes are made lively and sparkle again. In like manner, the Eyes do so clearly shew the Affecti∣ons of the Mind, as Sadness, Anger, Hatred, Love, and other perturbations, that those who are affected, though they should dissemble, cannot hide the feeling and intimate conceptions of the mind. Without doubt these so happen, because the animal Spirits, tending this way and that way in this diverting place between the Brain and the Praecordia, do at once strike those Nerves as the strings of a Harp. Wherefore from this kind of conjecture which we have made concerning the use of these Nerves, we have called them Pathetical, although indeed other Nerves also may deserve this name.

There yet remains for us to take notice of the aforesaid Prominences, that either of these pairs, and the Processes hanging on them, are distinguished from the Trunk of the oblong Marrow lying under by the Cavity between them; so that this Cavity or Ventricle seems to exist only secondarily, because the empty space between the aforesaid bodies, placed above and beneath, separating the same one from another, ought to come between. But this Cavity seeming to result so by accident, hath a very signal use; for in the middle of its passage a sloping aperture reaches towards the Tunnel, through which the humors slid∣ing into either of its holes, one made more forward, the other more backward, are sent out. The more forward hole is placed between the chambers of the Optick Nerves, a little before the Pineal Glandula, into which the serous heap being laid up nigh to the confines of the oblong Marrow, slides by degrees: but the other hole is opened more backward into the fourth Ventricle which is planted under the Cerebel; which hole is covered with a thin Membrane, which girding about its mouth and that of the Cerebel, provides lest the humors, derived from the fourth Ventricle, or the confines of the Cerebel, should fall down any other way than into that hole; but if at any time that little hole be broken asunder by a deluge of the Serum, the watry Latex sliding down upon the Basis of the oblong Marrow, overwhelms the origines of the Nerves, and so brings Convulsive distempers and meltings, and not seldom deadly, of the vital Spirits, as I have observed in the bodies of many dying of Cephalick Diseases.

CHAP. XV. Of the Uses of the Cerebel, and some of its Parts and Processes.

HAving hitherto continued the former Tract of the oblong Marrow, which as it were the Kings High-way, leads from the Brain, as the Metropolis, into many Provinces of the nervous stock, by private recesses and cross-ways; it follows now that we view the other City of the animal Kingdom. The situation of this being remote enough from the former, its kind of structure is also diffe∣rent from it: yea it seems that there are granted to this, as to a free and municipal City, certain Priviledges and a peculiar Jurisdiction.

The Cerebel is placed a little below the orbicular Prominences in the hinder part of the Head; where growing to the Trunk of the oblong Marrow by a double little foot, it appears almost of a Spherical fi∣gure. Its superior gibbosity coheres towards the superficies to the border of the Brain by the intervention of the Pia Mater, but nevertheless it is intimately united to it, nor is there any immediate commerce be∣tween this or that or their parts. There hath been spoken enough already of the figure and situation of the Cerebel, and of its various Processes, and how it is fastned to the oblong Marrow; it now remains that we proceed to design or draw out the offices and uses of it, and its several parts. Where in the first place shall be inquired into, what kind of office the Cerebel is endued with in the animal oeconomy; then when we shall descend to particulars, there are more things worthy to be noted, which will offer them∣selves

to our consideration: viz. first the infoldings of the Vessels covering the whole compass of the C•…•…∣rebel, and especially its hinder part, with the heap of Kernels: secondly, its folds and lappets ordain•…•…d with a certain and determinate series, and almost after a like manner in all: thirdly, the double substance of the folds, viz. cortical and marrowy: and the concentring of all the medulla•…•…y tracts in two large Marrows or middests: fourthly, either little foot or pedestal of the Cerebel made out of those two middle Marrows: and in either pedestal three distinct medullar Processes to be found: fifthly, the annular Pro∣tuberance made by a process of the Cerebel descending into the medullar Trunk: sixthly, some Nerves, which arising immediately from this Protuberance and other Nerves in the neighbourhood, which be∣ing designed for the involuntary Function, receive the influences of the animal Spirits from the Cerebel: Lastly, the Ventricle or Cavity lying under the Cerebel ought to be considered.

1. As to the office or use of the Cerebel in general: nothing of it occurs, spoken by the Ancients, wor∣thy its fabrick, or agreeable to its structure. Some affirm this to be another Brain, and to perform the same actions with it: but if any one should have a soft and foolish Brain, I greatly doubt, if he should become wise, though he should obtain perhaps a more hard and solid Cerebel. Others place the Memory in this part, supposing the Cerebel to be as it were a Chest or Box, wherein the Idea's or Images of things, before laid up, are kept apart from the incourse of fresh Species. But it is far more probable, that this fa∣culty resides in the cortical Spires of the Brain, as we have elsewhere shewn. For as often as we endeavour to remember objects long since past, we rub the Temples and the fore-part of the Head, we erect the Brain, and stir up or a waken the Spirits dwelling in that place, as if endeavouring to find out something lurking there; in the mean time, there is perceived nothing of endeavour or striving motion in the hinder part of of the Head. Besides, we have shewn, that the Phantasic and Imagination are performed in the Brain; but the Memory depends so upon the Imagination, that it seems to be only a refl•…•…cted or inverse act of this: wherefore that it should be placed with it in the same Cloister, to wit, in the Brain, is but necessary; for it plainly appears, that there is no immediate commerce between the Brain and the Cerebel.

When some time past I diligently and seriously meditated on the office of the Cerebel, and re∣volved in my mind several things concerning it, at length, from the Analogy and frequent Ratiocina∣tion, this (as I think) true and genuine use of it occurred; to wit, that the Cerebel is a peculiar Foun∣tain of Animal spirits designed for some works, and wholly distinct from the Brain. Within the Brain, Imagination, Memory, Discourse, and other more sup•…•…rior Acts of the animal Function are per∣formed; besides, the animal Spirits flow also from it into the nervous slock, by which all the sponta∣neous motions, to wit, of which we are knowing and will, are performed. But the office of the Cerebel seems to be for the animal Spirits to supply some Nerves; by which involuntary actions (such as are the beating of the Heart, easie Respiration, the Concoction of the Aliment, the protrusion of the Chyle, and many others) which are made after a constant manner unknown to us, or whether we will or no, are performed. As often as we go about voluntary motion, we seem as it were to perceive within us the Spirits residing within the fore-part of the Head to be stirred up to action, or an influx. But the Spirits inhabiting the Cerebel perform unperceivedly and silently their works of Nature without our knowledge or care. Wherefore whilst the Brain is garnished as it were with un∣certain Meanders and cranklings turnings and windings about, the compass of this is furnished with folds and lappets disposed in an orderly series; in the spaces of which, as in designed Orbs and Tracts, the Animal Spirits are expanded according to the Rule and Method naturally impressed on them. For indeed those in the Cerebel, as it were in a certain artificial Machine or Clock, seem orderly disposed after that manner within certain little places and boundaries, that they may flow out orderly of their own accord one series after another without any driver, which may govern or moderate their motions. Wherefore forasmuch as some Nerves perform some kind of motions according to the instincts and wants of Nature, without consulting the government of the will or appetite within the Brain, why may it not be imagined, that the influence of the Spirits is derived wholly from the Cerebel for the performing of these? For it seems inconvenient, that for these offices which should be performed without any tumult or pertur∣bation, the Spirits should be called out of the Brain, which are continually driven into fluctuations as it were with the winds of Passions and Cogitations.

As I only imagined of the use of the Cerebel after this manner, I was led to it at length by a certain thread of Ratiocination; to which afterwards happened an Anatomical inspection, which plainly confirm∣ed me in this Opinion. For in the frequent Dissection of the Heads of several sorts of Animals certain Ob∣servations did occur, which seemed to put this matter out of all doubt. For I first observed, the pairs of Nerves, which did serve to the Functions, wont to be performed by the Instinct of Nature, or the force of the Passions, rather than by the beck of the will, so immediately to depend on the Cerebel, that from thence only the influence of the Animal Spirits seems to be derived into their origines or be∣ginnings. By what means the Nerves arising from the Cerebel, or receiving from it the provision of the animal Spirits, do perform only involuntary actions, shall be declared hereafter; in the mean time, for the confirmation of this Opinion, we have in readiness another Reason of no less mo∣ment.

Therefore secondly, we took notice, that not only the conformation or make of the Cerebel was or∣dained after a certain and peculiar manner, that is, that its frame or bulk was couched together with folds or little circles, disposed in a certain distinct series, and apt method, and proportionate within them∣selves, as hath been said; whence it may be argued, that the Spirits arising from hence, and flowing out∣wardly, are imployed or bestowed on some certain works determinate to one thing. But further it is ob∣served, that in all Animals, although they differ in form and kind, yet the figure of the Cerebel is always very like or wholly the same. The Brain and oblong Marrow are figured in many after a divers manner; for as we have shewed before, there is some difference of these parts found in man and four-footed beasts; but between either of these, and Fowls and Fishes, there is a notable difference as to these parts. Not∣withstanding in all these the Cerebel, furnished wholly with the same lappets or little circles alike infold∣ed one in another, is marked with the same form and proportion; which certainly is a sign that the ani∣mal Spirits in this work-house are begotten and dispensed, as it were by a certain dimension, for certain necessary offices, which are performed in all after the same manner; and which cannot be any other than the motions and actions of the Viscera and Praecordia. As to the other Faculties, of which sort are Imagi∣nation, Memory, Appetite, yea local motions and sense are exercised after one manner in those living Creatures, and after another manner in others; wherefore their brains are formed after a divers manner. But the motions of the Heart and Respiration in all endued with an hot blood, are performed after a like manner, that is, with a perpetual vicissitude of Syftoles and Diastoles. Besides, another office is to be assig∣ned to the Cerebel, and different from what is convenient or agreeable to the Brain; because where the folds and turnings are wanting in the Brain, they are constantly found in the Cerebel. Besides these reasons drawn from Anatomy, the Pathology of the humane Body affords many others, which con∣firm the aforesaid office of the Cerebel. For it oftentimes happens that cruel and horrid Symptoms infest the Praecordia and the region of the middle or lowest Belly; whilst in the mean time, the morbifick cause lyes in the Cerebel, or nigh its confines. I have known sometimes men labouring only in appearance with a Dyscrasie of the hinder part of the Head, who complained of frequent Swooning and repeated meltings of the Spirits or Deliquiums, as if they were just dying: in whom notwithstanding nothing more could be detected of the morbifick cause or its seat, but that the Patient perceived a great heaviness and pain in the hinder part of the Head, and that upon any sudden motion or bending back of the Head, they were ready to dye. In truth, the Symptoms which are wont to be raised up in the distemper called the Incubus or Night-mare, viz. loss of speech, and a mighty weight or load that seems to lye upon the breast, proceed altogether from the morbifick matter fixed in the confines of the Cerebel, and obstructing the pas∣sages of the Spirits destinated for the Praecordia. But indeed this Hypothesis of the office of the Cerebel shall be more illustrated and confirmed from the uses of its several parts, being rightly designed or drawn forth.

As to the parts and accidents of the Cerebel, 1. we take notice, that the infoldings of the Vessels eve∣ry where cloath the Cerebel no less than the Brain, also that the ridges and furrows of its Folds inti∣mately hide or cover it, which certainly is a sign that the animal Spirits are begotten in this other work∣house of them from the watering blood, and instilled into its substance: which thing also more clearly ap∣pears, because the Arteries and Veins are not only variously complicated in the superficies of the Cerebel, but both of them in like manner as in the Brain, send forth frequent shoots into its more inward sub∣stance; wherefore whilst the most subtil and spirituous part of the blood being carried through long win∣dings about, and as it were serpentine chanels of the Vessels, and so sublimed into Spirits is received with∣in; the bloody part is carried away by the shoots of the Veins sent also deeply down. Further, even as the more watry portion of the blood, destinated for the Brain, runs into the Choroeidal infolding; (whereby it may there lay aside its unprofitable Phlegm into the Glandula's) so for the sake of separating the Phlegm an heap of Glandula's, with the foldings of the Vessels, as it were a Receptacle fitted for this business, is placed in the hinder Region of the Cerebel.

2. From the blood, after this manner cleared from Phlegm, and made subtil by a long circulation, very pure and spirituous liquor is instilled into the cortical substance of the Cerebel, which is presently exalted by the Ferment there placed into animal Spirits. For indeed we have affirmed, that the Spirits are procreat∣ed only in the cortical part of the Cerebel, as in that of the Brain: wherefore, because this kind of Cortex is wanting to the oblong and spinal Marrow, we think these parts do serve only for the exercise of the animal Spirits, and not for their production.

3. The Spirits every where produced within the cortical or exterior compass of the Cerebel, in which they are presently prepared for the work of the animal Function, are derived from all the folds into the medullar tract, and thence into two ample middle Marrows; where they keep full as it were the fountain or spring, and there like the bubling up of waters, are circulated within with a perpetual turning and from thence they continually stream forth into the parts of the nervous System proper to them∣selves.

4. As to the ways of Emanation it is observed, that the two middle Marrows of the Cerebel pa•…•…s as it were into two pedestals or little feet, by which they are fastned to the trunk of the oblong Marrow; and for that in either little foot of it three distinct medullar Processes are found, all these, or at least two of them, are as it were so many paths whereby the animal Spirits stream forth from their fountain and flow back a gain.

5. The first of these Processes ascends into the Cerebel from the orbicular Prominences, the use of this we have already declared; to wit, that there may be a certain passage between these Prominences and the Cerebel, in which, whilst the animal Spirits, as in a by-path, move this way and that way, to and fro, they may transmit both the force of the Passions from the Brain by the interposition of the Cerebel to the Praecordia, and convey also the natural Instincts delivered to the Cerebel from the Praecordia and Viscera towards the Brain. But the second Process descending straight from the Cerebel, embraces the medullar Trunk, and so going round about it, constitutes the annular or ringy Protuberance, out of which the fifth, sixth and seventh pair of Nerves take their originals; so indeed, that this Protuberance seems to be the Ware-house or Store-house of the Spirits flowing from the Cerebel, from which they may influ∣ence and be derived into the opposite passages of the Nerves. Lastly, the third process of either little foot, descending from the Cerebel into the oblong Marrow, is inserted into its Trunk over against where the eighth pair gf Nerves have their Original: so that it should seem very likely, the provision of the Spirits destinated for this Nerve is derived al•…•…o by this way from the Cerebel; then what Spirits superabound, remaining longer than this Nerve requires, they sliding down into the common belly or chanel of the oblong and spinal Marrow, increase the plenty of those parts. For this same end the smooth and pyra∣midal bodies are reached out of the annular Protuberance above the oblong Marrow towards the Spine, to wit, that by the passage of those Processes the Spirits of that provision or stock superabounding, might flow out partly into the beginning of the eighth pair, and partly into the common tract of the medullar Trunk.

Thus much we have spoken briefly and summarily of the Uses of the Cerebel, and of its parts and Processes. But that it may be the better understood, and also that this new thought of Theory concern∣ing the involuntary Function of the animal Regiment, may be more clearly illustrated, we shall here give you a more particular Order or Method of the Spirits brought forth in the Cerebel, and as it were take a view of, or muster their Arms or Forces. Further, it will seem to the purpose, that we should design or draw forth more openly the abundance or plenty of the Nerves receiving their gifts from this Fountain of the Spirits concerning the Acts to be performed only of the involuntary Function.

CHAP. XVI. Of the various Order and diverse manner of Exercise of the Spirits produced in the Cerebel for the Acts of the involuntary Function.

AFter having shewn, that the office of the Cerebel is to procreate animal Spirits apart from the Spi∣rits begotten in the Brain, and to dispense them into the Nerves, the Executors of the involun∣tary Actions and Passions; there yet remains to be unfolded by what manner of oeconomy or government the Spirits inhabiting the Cerebel and made free, are busied both by an intestine Circulation, within their proper dwelling places, and are wont to be expanded and flow out with an exterior irradiation for the necessities and wants of other parts: then these things being shewn, we shall design more parti∣cularly the Uses and Offices of the Nerves, and of some other Processes doing service to this Govern∣ment.

As to the first, as the Cerebel is the other primary Root of the sensitive Soul, or the Fountain from whence the animal Spirits, being diffused through the whole substance of it and its Appendix, are con∣tinued still under the same systasis and radiant Contexture, it is to be noted, that this radiation of the Spi∣rits from the Cerebel doth flow after another manner than the other from the Brain: because this being left to it self, is bestowed by a constant efflux or flowing out on the Organs both of the vital Function and the merely natural, and its expences by an equal continual provision of Spirits, are made up again from the bloody mass continually instilled in. But on the contrary, the Spirits flow out from the Brain, neither by such a continual course without intermission and by little and little, nor are sustained by a per∣petual provision and sliding in by degrees; but both the loss of them, and their refection, are uncertain, unequal, and variously interrupted. For neither are the spotaneous Acts of the Function it self, to which they serve, performed after any constant or always the same manner; but according to exterior accidents and occasions we put them forth by heaps, and with a certain force sometimes, and again sometimes we suffer them to be wholly intermitted and unimployed. Therefore the Spirits also are in like manner sup∣plied with an uncertain measure; to wit, they are instilled in sleep plentifully and more copiously, but waking more sparingly and with hard labour, or scarce not at all. Yea the involuntary portion it self of the sensitive soul (which flows from the Cerebel) for that it hath a near commerce and affinity (as was already said) with the other radicated in the Brain, therefore it is wont to be much disturbed in the performing

its office equally and peaceably, and being variously affected and agitated by the impulses sent here and there, or from this place and that, it is compelled, sometimes to contract, sometimes to extend its Sy∣stafis in the whole or in part, and so is rendred obnoxious to several Passions, and ordinarily instigated to the performing irregular and disorderly actions.

But indeed the contexture of the Spirits, or the part of the Soul irradiating the Cerebel and its Appen∣dix, is both affected with a certain sense, and is urged into motions appropriate to it self, though divers. The sense or Sympathy belonging to this, if it be terminated within the confines of the Cerebel, is always private, nor goes any farther forward to the Brain with a more strong undulation or wavering; and be∣cause it is performed the living Creature knowing nothing of it, unless by the effect it cannot be known, for that it excites a peculiar motion. But such an affection of the Cerebel is implanted in it, that by every new disposition of the Praecordia and Viscera communicated to this from beneath, also from every violent passion excited within the Forum of the Brain, and so sent from above, a certain impression is carried to the inhabitants of the Cerebel: by which indeed they are disposed into various ordinations for the per∣forming these or those motions respectively.

For examples sake, so long as the tranquil region of the Cerebel, like a serene and fair Heaven, is free from all perturbation, the Spirits its inhabitants, being poured out with a pleasing sense, or as it were a certain complacency, flow within their proper habitations, both with a gentle circulation, and also with an equal flowing out enter the beginnings of the Nerves serving to the Functions both vital and natural: by which indeed easie Respiration, the Pulse, Chylification, and other offices of the same nature, are per∣formed peaceably. But if that any trouble or molestation happen outwardly to any one, from whence an impression of it is communicated to the Cerebel, presently a troublesome sense being stirred up there, it disturbs the animal Spirits in the Fountain it self, and so is wont to excite irregular motions in the Or∣gans of the involuntary Function. For from hence the frequent alteration of the Pulse and of Respiration, also Cramps of the Viscera, and convulsive motions arise unknown to us, or also against our wills. But an impression sent from elsewhere to the Cerebel, and inducing the same kind of a troublesome sense, either ascends by the passage of the Nerves from the Praecordia and Viscera, or it is carried from above from the Brain by the passage of the orbicular Prominences; as shall be shewn more largely anon.

In the mean time, from these things already shewed of the passive power or sense of the Cerebel, it may be easily collected, by what means, with what order and series the animal Spirits, arising from the same, are moved. But first you must distinguish between their twofold motion. For one is custo∣mary and ordinary, consisting in a perpetual and equal efflux of Spirits; by which indeed, they flow∣ing into the beginnings of the Nerves nigh their risings, especially of the intercostal and wandring pair, the solemn acts of the Pulse, Respiration, Chylification, and others of the involuntary Function are perform∣ed. Then secondly, the other motion happens extraordinary and occasional, which the same Spirits per∣form confusedly, as it were in disturbed orders: as when the Pulse becomes quicker or slower than it ought, or the Respiration unequal or interrupted; and when the other Faculties, which belong to this Class, are perverted from their regular and constant manner. But these kind of extraordinary motions are again twofold, to wit, for that its instigation proceeds from a double bound; for the impulse whereby the Spirits inhabiting the Cerebel, are compelled into an irregular action, (as we have but now intima∣ted) is carried either from beneath, viz. from the Praecordia and Viscera; or it is wont to be transmitted from above, to wit, from the Brain.

As to the first, if at any time the Praecordia grow too hot, and are burnt with a feverish heat, presently by the passage of the Intercostals and the wandring pair of Nerves, the Spirits residing in the Cerebel, being warned of this evil, institute more frequent and stronger acts both of the Pulse and of Respiration. In like manner, if by chance the humors and sharp Juyces irritate or greatly trouble or afflict the Coats of the Ventricles or Intestines through the sense of this affection communicated to the Cerebel, the instinct of performing the motion is reciprocated, whereby the fibres of the parts, being contracted and wrinkled together, endeavour the shaking off of the hurtful matter. More instances might be here brought of all the other acts of the vital or merely natural Function, of which besides it may be observed, that when a sense of the trouble is immediately conveyed from the Praecordia or Viscera to the Cerebel, this affection, like the waving of waters, is either stopt or terminated there, from whence a motion, as the business requires, un∣known to the Brain, is presently retorted, as when the actions of the Praecordia are altered by a feverish distemper without our knowledge; or secondly, that sense of the trouble being transmitted to the Cere∣bel, for that it is more vehement, it unfolds it self more largely, and like a strong waving of waters, passing through the Cerebel, goes forward further even to the Brain, and warns its inhabitants of the evil; by which they being incited to oppose the enemy, cause a motion of another kind: So (as hath been said) when the Praecordia grow cruelly hot, the Cerebel feeling this, makes the Pulse and Respiration stronger. But further, the Brain being warned of the same trouble, seeks and diligently requires cold drink and other remedies to moderate the heat. Moreover, it is after this manner also in several other actions, which though they are regular, yet being made in the Brain without any previous knowledge, they are said to be done by Instincts merely natural; as when brute Animals, being newly brought forth, pre∣sently seek for the Dams Teats, and greedily suck; or Birds, without any shewing or Example, build Nests with wonderful Art, lay eggs, and hatch young ones. In these kind of works the Brain being

taught before by none: directs fit means to the ends instituted by Nature: which indeed seems to be done by this means. The sense of every necessity being brought to the Cerebel, incites the Spirits in∣habiting it to succour it; which when they are not able to do, the impression going from thence further forward, is carried to the orbicular Prominences: by which the Spirits there inhabiting, being present∣ly struck, form the Appetite or the intention of performing, which being thence communicated to the Brain, it readily causes that local motions, fit for the executing of the work, be retorted. Of these we shall speak anon a little more largly, when we treat of the respect which happens between the orbicular prominences and the annular Protuberance.

In the mean time, we shall take notice in the second place, that the irregular motions of the Spirits, inhabiting the Cerebel, are wont also, by reason of the force of the affections, to be transmitted from thence to the Brain: for as often as a violent passion, as Joy, Sadness, Anger, Fear, or of any other kind, is conceived in the Brain, presently the impression of the same being brought through the by paths of the Prominences into the Cerebel, disturbs the Spirits destinated to the vital or merely natural Function in their very fountain, and for that reason presently induces notable mutations in the Organs of those Functions.

What hath been spoken hitherto of the Cerebel being imployed about the offices of the involuntary Function only, also concerning the sense and the motions both usual and irregular of the Spirits inhabit∣ing it, will be made more clear, if lastly we shall shew the offices of the Nerves and of the other processes, immediately depending upon the Cerebel, to be no other than such as perform only involuntary Acts: which shall be briefly and succinctly done, as far as is pertinent to our purpose, because a more full conside∣ration of them is left to another place.

CHAP. XVII. Of the Nerves, which receiving the stores or companies of the Spirits from the Cerebel, bestow them on the Acts of the involuntary Function.

WE have already shewed, that out of the annular Protuberance (which is a certain Process of the Cerebel) three pairs of Nerves, to wit, the fifth, sixth, and seventh immediately arise. We have said that Protuberance to be as it were a r•…•…pository or Store-house, wherein the Spirits flowing out of the Cerebel, and to be derived into the depending Nerves, as occasion serves, are kept: and in the mean time, whilst they remain there, they who stream out from either mid∣dle Marrow of the Cerebel divisively, meeting mutually in this Cirque, are united together. But as the aforesaid three pairs of Nerves receive the forces of the Spirits from the Cerebel by the mediation of that Protuberance▪ so also the eighth pair having its rise near the insertion of the other (viz. the lowest) medullar Process sent down from the Brain, seems to derive by its passage the influence of the Spirits no less from the Cerebel: wherefore when these four conjugations of Nerves owe the Tribute of their Spi∣rits wholly to the Cerebel, if I shall shew that all these Nerves serve chiefly and almost only to the in∣voluntary acts of the Senses and Motions, surely this will be a signal Argument, that according to our Hypothess, the office of the Cerebel is to beget and to dispense the animal Spirits requisite for the invo∣luntary Functions.

Therefore in the first place we observe of the fifth and sixth conjugation of Nerves, that as this arises out of the Basis of the greater Ring, and that from its sides both in man and in four-footed beasts; the fifth pair being carried more forward, distributes its branches into the Glandula's of the Eyes, into the Nostrils, into the Palate, Teeth, yea and into most parts of the Face and Mouth; but the sixth pair is wholly bestowed on some Muscles of the Eyes. Further, out of the trunk of the fifth pair two shoots, and another out of the Nerve of the sixth pair bending back behind, meet together; and what is won∣derful, and not before taken notice of by Anatomists, the intercostal Nerves, destinated to the Praecor∣dia and Viscera, do make a Trunk; so that the Nerves, of the fifth and sixth pair stretch out a double Ramification, to wit, one more above about the parts of the Mouth and Face, and the other lower through the Viscera of the middle and lowest Belly. But it will appear clearly to any one considering this thing more carefully, that the chief branches of either partition are imployed about the invo∣luntary offices of Motion and Sense, of which sort those are chiefly, that either cause the passions, or per∣form the natural Instincts.

1. Concerning the intercostal Nerve, which (as was said) being radicated in the Nerves of the fifth and sixth pair, depends as to its origine wholly on the Cerebel, it is not here to be doubted but that it looking towards the Praecordia and Viscera in a man, and towards these latter only in most four∣footed beasts, is bestowed on the Functions only vital and merely natural, and so confers little or no∣thing

to spontaneous Actions. Further, forasmuch as this Nerve reaching forth into Praecordia and Viscera of the whole Abdomen, is continued by its superior ramification also into the Eyes, as also into the parts of the Mouth and Face; certainly from hence a true and genuine reason may be given wherefore in every passion the Eyes, Face, and Mouth do so correspond with the affections of the Praecordia, often unknown to us or against our minds, that oftentimes we are compelled to betray the most intimate sense of the Heart by the continuance and aspect. Yea, hence a reason may be brought, why in sneesing, yawning, laughing, and crying the Muscles of the Face conspire so in motion with the Praecordia. Besides, when in man different from any other living Creatures besides, as we shall shew afterwards, many shoots are sent from the intercostal Nerve to the Nerve of the Diaphramga; this certainly is the cause why risibility is the proper affection of man.

But the Trunk of the fifth pair being carried more forward, and distributing its branchings through the parts of the whole Face, causes the same not only to be pathetically moved, and figured according to the affections of the Praecordia; but also produces some acts, both of motion and sensation, of another kind, which for the most part are involuntary, and so seem to depend wholly upon the Cerebel imme∣diately. For example, this Nerve imparts shoots to either mandible requisite for the business of chew∣ing: but it is very well known, that the taking in of the food at the mouth is the first and oldest busi∣ness of every Animal, which indeed is taught by natural Instinct before any knowledge of the Brain. But as to the Senses, the branches of this pair conduce something to the smelling, but for the most part for the knowing and chusing of savors. Hence it comes to pass, that as odors refresh the Brain by the smelling Nerves, so also they affect the Cerebel by the branch of this pair, and are wont by that means to recreate the Viscera and Praecordia. But sapors or tastes (for that they are almost the peculiar Province of this) carry whatsoever they have of pleasantness or trouble, first to the Spirits inhabiting the Cerebel, and then by their consent to the Praecordia and Viscera. Hence it is, that a Pectoral not only allays hunger, but the very first tasting of Wine raises up those that are fainting or swooning away. Moreover, forasmuch as from this Nerve certain branches serve for the taste, and others for the smell, there is contracted so strict an affinity between either of these Sensories, that nothing pleases the taste unless it be approved of by the smell: and the loss of one of these senses oftentimes causes the privation or the diminution of the other.

2. Concerning the Nerve of the sixth conjugation we observe, that as one shoot is bent back for a root of the intercostal Nerve, the remaining Trunk of it being carried forward towards the ball of the Eye, is distributed to two of its Muscles, viz. to the seventh, proper to beasts, and to the drawing Muscle. Hence may be inferred, that this Nerve, besides the influence of it bestowed on the vital and natural Function, serves also for the producing some pathetick motions of the Eye, to wit, such as are wont to obey the affections of the Praecordia and Viscera; so that the whole provision of the animal Spirit, which it receiv•…•… from the Cerebel, it bestowes only on involuntary acts.

3. The seventh pair, or the hearing Nerves, seem also to depend upon the Cerebel, for asmuch as they take their originals out of the annular Protuberance: but the use of th•…•…m is a little otherwise in man than in four-footed beasts. For in him the annular Protuberance is one, and that very big, from whose lower margin the auditory Nerves proceed: but in Brutes the Protuberance is twofold, viz. one greater, sent down from the Cerebel, in which the beginnings of the fifth and sixth pair of Nerves consist; then near this there is another lesser, and as it were secondary, from which the auditory Nerves proceed. This lesser and lower Ring doth not so manifestly depend on the Cerebel, as the former; but there is stretched out from either height of it a white medullar line upon the oblong Marrow in the bottom of the fourth Ventricle: so as this seems to receive either the Spirits from the oblong Marrow, or at least to carry into the same the sensible Species: for what use it is so constituted shall be inquired into afterwards; for concerning these Nerves of the seventh pair, forasmuch as some offices of them very much illustrate the goverment or oeconomy of the Cerebel, we shall discourse here a little more largely.

Therefore in man, who hath got a great and undivided annular Protuberance, and auditory Nerves coming out of its margin or brim, shews its stock received of the Cerebel: by which means we may see the tasks of those Nerves quadrate with the assigned government of this. We have shewn before the Processes (which in a manner may be called distinct Nerves) of the seventh pair to be twofold on either side: one, the softer of these, serves only for the sense, but the other harder seems to perform some motions. This latter Nerve, being carried without the Skull, is divided into three branches, all which serve to pathetick motions, or at least to such as are performed without consulting the Brain.

1. The first of them being bent back towards the auditory passage, is bestowed on the Muscles of the Ear. Without doubt, by the action of this, it is effected, that all Animals at the sudden impulse of a sound or noise, erect their Ears as it were to catch the sound too soon passing by. 2. The other branch of this same N•…•…rve climbing over the Muscles of the Jaw, sends forth shoots towards either corner of the Eye: which are inserted into the muscles lifting up the Eye-lids; the office of which is certainly to open suddenly the Eyes at the sudden approach of any sound, and as it were to call them forth to watch, that by the stroke of the Air being brought to the Ear, the Eye might presently look about to see what is the matter, and whether there might be any danger near or not: which also all creatures do unthought of. 3. The third branch of the same auditory Nerve descending towards the root of the Tongue, is distributed to its Muscles, and to those of the Bone Hyoides, and so actuates some of the Organs for the framing

the Voice. For this reason in some measure it comes to pass, that living Creatures being astonished at an unaccostomed or horrid sound, presently putting forth an uncertain voice, cry out and make a noise. But the conformation of these kind of Nerves in man serves for another more noted use, to wit, that the voice might fi•…•…ly answer to the hearing, and that this might be set as the Echo of the sound admitted by this: so indeed, as on the other side, there be two Nerves of the same pair, the sound is received by the hearing, through one, which is rendred again by the voice through the other. The common and extrinsick Echo consists in this, that a certain undulation or waving of the Air shaken or moved, being stirred up, and tending towards or about, when by reason of some stop or hinderance, it cannot go any further directly, being presently repercussed or struck back or reflected at certain angles, it is terminated contrary to the former bound. In like manner, in the hearing, the impression of the sound, or the Species admitted to the Ears by the hearing faculty of the Processes of the same or neighbouring Nerve, and being carried inwardly towards the Cerebel and common Sen∣sory, and from thence again reflected on the vocal process, it is carried out by the Mouth. But between these there is some difference, to wit, forasmuch as the outward Echo renders back the sound imme∣diately; but the sound of the Hearing is not necessarily carried forth at the mouth presently, but that this leaves an Idea in the Head, according to which afterwards, as occasion serves, the voice is for∣med, which bears the type and image of that, though some time before admitted.

But here (if I may digress a little) we should inquire in what part of the Head the Ideas of sounds are left: whether only in the Brain, which is the Chest of Memory accquired as it were artificial, or whether not also in the Cerebel, which is the place of natural memory? Truly we suppose, that sounds belong to both these, as it were to distinct Store-houses. Every audible impulse being struck against the Ear, it is presently carried by the passage of the auditory Process to the annulary Protuberance; but from thence it is carried, as other sensible Species, to the chamsered bodies or the common Sensory; (which way it passes thither, shall be shewed afterwards) this impression tending from thence farther, and being also de∣livered to the Brain, stirs up the Imagination, and so leaves in its Cortex an image or private mark of it self for the Memory. Further also, as the auditory Process depends on the Cerebel, and receives from it the provision of the animal Spirits: so it is most likely, that by the recess of the same Spirits the Ideas of the Sounds are conveyed also to the Cerebel; which forming there foodsteps or tracts, impress a remem∣brance of themselves, from whence when afterwards the Species there laid up are drawn forth by the help of the vocal process, voices, like the sounds before admitted, and breaking forth in a certain ordain∣ed series, come to be made.

Hence it is usual, that musick or melody is soon learnt by some men, which afterwards they bring forth with exact Symphony, without any meditation or labour of the Brain; to wit, from the distinct accents of the heard harmony, the Spirits moving within the Cerebel are disposed into peculiar Schemes; according to which, when they flow on both sides into the vocal process of the auditory Nerve, they ren∣der as it were with a certain spontaneous voice, and like a Machine or Clock with the succession of Spe∣cies, the measures or Tunes of the Instrument which they had drunk in at the ears. Without doubt hence the reason may be sought, why some men learn Musick without any trouble, and others hardly or not at all. For it is observed, that some Children, before they can speak distinctly, quickly sing, and remember certain Tunes; whilst others, though very ingenious men and of excellent memory, are very Fools at Musick, and become uncapable, as an Ass for the Harp; wherefore 'tis commonly said, that some have mu∣sical ears, and others are wholly destitute of that faculty. In the mean time, 'tis to be confessed, that in these the Organs of the Voice are not defective; but all the fault, though wrongfully, is cast on the hearing.

But in truth the genuine cause of this defect seems to consist in this, that when in all, the audible Spe∣cies go to the Cerebel sooner and more immediately than the Brain; yet in some the Cerebel being har∣der, and not easily yielding to the received impressions, those Species, because they could impress nothing of themselves in their passing to the Cerebel, being carried towards the common Sensory, leave their Types or Ideas chiefly and almost wholly in the Brain: which part being still busied with disturbed motions, is less apt to keep distinctly the composures of Harmony. But in the mean time, in others the Species of audible things, besides that they are carried to the common Sensory and to the Brain, do also affect the Cerebel, especially if they are harmonically figured (forasmuch as in them there is a softer capacity of the impressions) with a peculiar order and Scheme of the animal Spirits: where, as the Species of the Harmony being disposed in convenient little places and cells are kept, afterwards they flow out from thence, almost unthought of, without any endeavour or labour of remembrance, but in a distinct series, and as it were in composed modes and figures, and so by blowing up the vocal processes, they constitute sweet Tunes and vocal Musick.

If that the divers ways of passage are inquired into, to wit, whereby the audible Species, being carri∣ed into the annular Protuberance, do get both to the Brain and Cerebel; I say it is not improbable, but out of that Protuberance both a passage lyes open into the underlying tract of the oblong Marrow, and as it were the high road as also another passage is opened into the Cerebel through the medullar processes of the same Ring. But lest there should perchance be a confusion of the animal Spirits and the sensible Speci∣es, (which indeed can hardly be avoided) if the way made for their passage should lye open into various passages and manifold apertures; therefore concerning this it may well be supposed, that the Ideas of the Sounds pass through the Cerebel, when they are carried to the common Sensory; which region being first

past, they are at length brought by a by-path, viz. through the orbicular Prominences to the chamfered Bodies: which perhaps is partly the reason, that in the Hearing the perception of the sense succeeds so late, and the impulse of the object, in respect of sight, follows so slowly.

Whilst therefore the audible Species passes through the Cerebel, in some men, it leaves in this region (for that it is of a soft temper, and fit for the receiving impressions) and tracts and marks of it self, and so they obtain musical ears. But in others who have a harder frame of the Cerebel, they produce no tracts of the same Sounds, and therefore such are wholly distitute of the faculty of Musick.

As therefore we suppose the audible Species to pass through the Cerebel after this manner, a reason may be given from hence, wherefore Musick does not only affect the Phantasie with a certain delight, but besides chears a sad and sorrowful Heart; yea, allays al•…•… turbulent Passions excited in the Breast from an immoderate heat and fluctuation of the blood. For since the animal Spirits, serving for the motion of the Praecordia, are derived from the Cerebel; as the perturbations conceived in the Brain, the influence being transmitted hither by moving these Spirits, in the Fountain it fel•…•…, transfer the force of their Affections on the Breast; so the Melody introduced to the Ears, and diffused through this Province, does as it were inchant with a gentle breath the Spirits there inhabiting, and composes them, called off from their fury, to numbers and measures of dancing, and so appeases all tumults and inordinations therein ex∣cited.

From these may in some measure be known the reason of the difference, why the hearing Nerves are after a different manner in man and in four-footed beasts: for, because in these there is little need that the audible Species should pass through the Cerebel, either for the reciprocations of the sound heard, by the voice, or for the impressing there the Tunes of the Harmony (for neither is Musick required, what ever Poets feign, to the taming the Affections which move the breasts of beasts) therefore in these (I mean in four-footed beasts) the annular Protuberance dispensing the animal Spirits to the auditory Nerves, and receiving from them the sensible Species, requires not so strict an affinity with the Cerebel: yea, whenas in may suffice, that those Nerves arise from the oblong Marrow, yet the annular Protuberance, as it were a common Porch, ought to be prefixed to them; to wit, in which both the Spirits going out from either side, and the sensible Species to be carried to either, ought first to be mixed and united together, lest otherwise every sound should become double.

Among the Nerves which are seen to belong to the Cerebel, and to perform its offices, lastly follow the eighth or wandering pair, which indeed hath its rise out of the common Trunk of the oblong Marrow, near the place where the last process of the Cerebel is terminated, and over against where the pyramidal bodies, being produced from the annular Protuberance, end: so that we think these Nerves also, by that process coming between on either side, and also perhaps in some measure through the passage of the py∣ramidal bodies, do derive all manner of influence of the animal Spirit from the Cerebel.

The beginning of these consists of very many fibres and filaments or little threads presently distinct one from another; to which belongs, from the very beginning of every Nerve, a noted Trunk arising out of the spinal Marrow. The description of the wandring pair of Nerves, and its protension into the Praecordia and some Viscera, are added hereafter. For the present it shall suffice, that we take notice, for that as much as this Nerve is bestowed chiefly on the Praecordia, the acts whereof are involuntary, and are per∣formed without our care or knowledge in sleep as well as waking; and for that the same Nerve seems to receive the forces of the Spirits wholly from the nearer fountain of the Cerebel; from hence it may certainly be well concluded, that the government or oeconomy of the Cerebel regards only the involun∣tary Function.

So'much for the Nerves, which being subjected to the Government and Laws of the Cerebel, seem to obey and serve under it: among which moreover ought to be placed the fourth pair, or the pathetick Nerves of the Eyes, to wit, which arising out of the first processes of the Cerebel, come between that and the orbicular Processes; of the use of which we have spoken already. Further, we shall here take no∣tice, that some other Nerves to be described below, for that they communicate with the aforesaid Nerves near their originals, cause also some involuntary acts to be performed; of which sort are first the ninth pair, the spinal Nerve accessory to the wandring pair, also the Nerve of the Diaphragma, and some others, as we shall shew mor at large in the particular History of the Nerves.

We may also observe, concerning the Nerves but now described, which owe their stock to the Cerebel, and seem to be designed for the offices of the involuntary Function, that sometimes some of them, though of another Dominion, are compelled to obey the beck and government of the Brain: for we are wont to draw the parts of the Face, usually moved pathetically and unthought of, and also at our pleasure, into these or those Configurations or postures: we are able also in measure to alter the motions and actions of the Praecordia and Viscera at the will or command of the Appetite. The reason of these is, partly be∣cause the Nerves of either Government communicate variously among themselv•…•…s with shoots sent forth one to another, so that oftentimes the offices of the one are drawn into the parts of the other. But be∣sides, we have mentioned before, that the sensible impression being inflicted on the parts of the involun∣tary Function, forasmuch as it is vehement, like a strong waving of water, passing through the Cerebel, affects the Brain it self. In like manner it may be thought concerning the motion which belongs to those parts, viz. that made after the ordinary manner, that it is performed by the command of the Cerebel. Notwithstanding s•…•…me more severe Edicts of the Brain, by the by-passage of the Prominences, belong

also to the Cerebel, and determine the Offices of the Inhabitants of it to be performed at the beck of the Appetite. As every one sees that violent Passions (whether the will be privy or not) easily do this; why therefore may not the will it self also, as occasion requires, exercise the same dominion? But in the mean time, this derogates nothing from the priviledges of the Cerebel, that it may not be called a free and municipal City, and so Mistress of the involuntary Function; for that in some few it is after the manner of the Brain: because the Brain it self in many things is compelled to serve the Cerebel and its Government, as we have already shewn, and is necessarily bound to it. For the Brain owes much to the Cerebel, forasmuch as it receives from the vital Function (which is of its Province) the provision of the blood, and by consequence the Tribute of the Spirits produced of it: so indeed that both these parts, though Principals, perform mutual offices, and as it were in a circle, require and accomplish services one for another.

CHAP. XVIII. Of the relation or mutual respect of either Appendix of the Cerebel, to wit, of the anterior, which are the orbicular Prominences; and the posterior, viz. the Annular Protuberance: Also of the remaining portion of the oblong Marrow continued into the Spinal Marrow.

BEsides the aforesaid Nerves, to wit, the fourth, fifth, sixth, seventh, and eighth pair which are imployed for the performing the tacit Edicts of the Cerebel for every involuntary Function, and those equal in number to the rest subject to the Brain, that cause the Cerebel to have an Empire divided with it; there are also some Processes and Protuberances, which being placed before and behind the Cerebel, are its Appendixes, that are taken into part of the same Office and Ministry. The de∣scription and use of these, are already particularly delivered. But for that (as a while since we intimated) there happens a certain respect or habit between the orbicular Prominences, which is the anterior Appen∣dix of the Cerebel, and the annular Protuberance, which is the other posterior Appendix of the same, and that one part is proportionate to the magnitude of the other; so as when the natiform Prominences are greater or greatest, the annular Protuberance is always smaller or smallest; and on the contrary, they who have this latter in a very great bulk, in them the other is lesser; and so for that either part seems to be a peculiar Repository of the Spirits, which belong to the oeconomy of the Cerebel, when a greater provision of them is laid up in one Store-house, therefore there resides a lesser in the other; when I say there is this kind of constant relation found between these parts, it yet remains for us to find out for what end this is so constituted.

Seeing that the animal Spirits are disposed within the several parts of the Head in distinct Schemes of Rays, through which are variously transmitted, as through Perspective glasses, the impressions of sensible things and the instincts of motions to be performed; it easily occurs, that there are commerces had this way and that way in the natiform Prominences between the Brain and Cerebel; and that the Spirits in∣habiting the annular Protuberance are Internuncii or Messengers going between, which transfer the mutual respects of the Praecordia and Viscera, as also of the parts that are wont to be pathetically moved. But if it be inquired into, what kind of commerces and respects those are which the Brain carries to the Cerebel, and on the contrary, and that either have to the Organs of the vital and merely natural Function, we shall in so difficult and very intricate a matter propose our Opinion, though with an hesitating and doubt∣ful mind.

We have before intimated, that the orbicular Prominences did deliver to the Cerebel the forces of the Passions to be carried from the Brain the Praecordia, and did receive from it, and communicate to the Brain the necessities of the natural Instincts delivered from the Praecordia and Viscera to the Cerebel. To these moreover we add, that the annular Protuberance serves wholly for the same offices, though after ano∣ther manner; to wit, this receives the forces of the Passions, as it were at a second hand, from the Deputiship of the Cerebel, and transfers them then immediately to the Praecordia; and this seems to be the chiefest office of this part. Further, the same Ring receives immediately the natural Instincts from the Viscera of the middle and lowest Belly, and impresses them on the Cerebel to be conveyed further to the Brain; which kind of use it exhibits secondarily by affording only a way of passage: For indeed such Instincts having past through the Cerebel, we suppose to be formed and perfected within the orbicular Prominences, from whence being transmitted into the Brain, they draw forth requisite actions without the previous knowledge of it, or intention of doing.

Hence it may be supposed, that the annular Protuberance contains chiefly the animal Spirits which perform the intestine commotions of the Affections. In every violent passion of the Soul, presently the Praecordia are greatly troubled, to wit, the same being variously drawn together or spread abroad com∣pel the blood into divers fluctuations; but indeed a great company of the Spirits, somewhere got together and ready for Excursions in a set Battel, do perform these disorders and irregular motions of the Praecor∣dia; and for that the Spirits can be disposed for this in no other part than here, before the beginnings of the Nerves, constituted for these offices; therefore this Protuberance in a man, by reason of the ragings of the passions to be performed by a certain force and incitation, is far greater than in any other Animal. For as he is wont to be suddenly and vehemently disturbed, therefore the Promptuary or Store-house is required to be more large, in which a greater plenty of Spirits may be kept, to be bestowed on such in∣ordinations of the Affections. Next to a man this part is greatest in a Dog, Cat, and Fox; in a Calf, Sheep, Goat, Hare, and other milder Animals it is very small.

But as the annular Protuberance seems to be the chief Organ or Chest of the Spirits, from whence the winds of the Passions, destinated for the exciting the Praecordia, are conveyed into the breast; so we sup∣pose the orbicular Prominences to be a means of passage, and the very instruments whereby the instincts and necessities of the Praecordia and Viscera are communicated from the Cerebel to the Brain. Yea, the animal Spirits dwelling in this, as a retiring place, do not only transmit these kind of Ideas or formal Reasons of the Instincts, but in some measure form and prepare them for the Brain. For when as some brute Animals, whose Brain is not imbued with a previous knowledge or practical habits, chuse and bring forth some spontaneous actions as it were with judgment and deliberation, certainly we may be∣lieve the intentions of these kind of acts are suggested from some other place than the Brain, to wit, from the aforesaid Prominences. Wherefore 'tis to be observed, that in some Brutes endued with an indocil or dull Brain, the Buttock-like Prominences are greatest, as may be seen in a Calf, Sheep, Hog, and many others▪ which Animals, as soon as they are brought to light, presently seek for their food, and what is congruous for them they readily know. But in a Man, a Dog, Fox, and the like, who are more apt to learn and acquire habits, these Prominences are very small; and these Animals being newly born, are furnished only with a rude and imperfect sense; besides, they are found wholly unapt to seek out their food. Upon this Observation (which holds good in most Animals which I have yet happened to dissect) as upon a Basis or foundation I dare build this kind of abstruse Hypothesis concerning the natural In∣stincts and Affections of the Praecordia. For as the living Creatures which are more strong in instinct, as Sheep, Hogs, Oxen, Goats, and other slow and gentler beasts, that are not obnoxious to Passions, are also less docile or apt to learn; and on the contrary, they in whom the Affections are wont to predominate, and who are furnished with a certain wit, (as besides Man, are Dogs, Foxes, and some other hotter Ani∣mals) are less powerful in Instinct: and as I have observed in the frequent Dissection of all sorts of Heads, that in those kind of living Creatures, who live rather by Wit than Instinct, the annular Protuberance, placed below the Cerebel, was notedly great, and the orbicular Prominences only very small; but in other living Creatures, where the Instinct exceeded the wit, and who were less prone to strong Affections, the orbicular Prominences were very great, and on the contrary, the ringy Portuberance exceeding small: From hence I was forced to think, that the orbicular or natiform Prominences, where they are great, are instead of another or supplementory Brain, and the chief Organs of the natural Instincts; yet so, as these parts also serve for a way or means of passage for the transferring the Passions from the Brain towards the Cerebel and Praecordia; and that (as we have all ready hinted) the greater existency of the annular Protuberance is to contain plenty of Spirits requisite for the winds of the Passions; yet in the mean time, by a further tending forwards or deciination of the Spirits inhabiting this, the Species of the natural Instincts, being sent from the Praecordia and Viscera pass through. But however the business is, because no∣thing can be certainly affirmed, or by demonstration, if this our Opinion please not others, at least it may be pardoned.

There remains not much more to be spoken concerning the Offices and Uses of the Cerebel and its Appendix. Concerning its substance, there is something more worthy taking notice of, to wit, that it very much differs in this respect from the structure of the Brain also, for that its cortical little circles are not founded in the stretched out Marrow, as the convolutions of the Brain; but being deeply cut in, are discontinued in their whole tract: so that the whole System of the Cerebel is as it were a cluster of Grapes compacted closely together; in which, although the Berries be contiguous, yet they remain dis∣tinct one from another, and bring forth fissures through the whole thickness of the mass. Yea the out∣ward superficies of the Cerebel consists as it were of very many Tubercles or little Tad-stoles or Puffe•…•… which grow together on little stalks; and those stalks pass into greater branches, and they at length be∣ing bipartite or twofold, go together into two larger Marrows near the bottom of the Cerebel, in either of which are three distinct medullary Processes: of which threefold processes on either side we have al∣ready spoken. But of these concerning the use of the Cerebel in general, we shall yet further advertise you, that as very much of its substance is cortical, it begets animal Spirits in great plenty, to which in the circulating there is not granted, as in the Brain, an equally great space; for that there seems not to be much need of it in the animal Government. For the Spirits so produced in the Cerebel plentifully by a perpetual emanation, ought to flow outwardly for the offices of the natural and vital Function: but more in wardly for the impulses variously sent into them, they admit certain undulations or wavings, by which some occasional acts of the involuntary Function are brought forth, as is shewn before.

But as it is manifest enough, that the animal Spirits are generated within the cortical little circles of the Cerebel, it doth not seem needful that we should ordain their Work-house in the Ventricle subject to its frame. For that Cavity (as we have already shewn) is only an empty space, which lying under its double little foot and medullar Trunk, comes between it and the overlying bunching out of the Cerebel. But indeed there belongs to this besides a certain use, to wit, that the serous watry heap laid aside out of the Glandula's and infoldings of the Vessels, as also from the substance of the Cerebel, being made over∣moist, distilling down, might slide into this Cistern. From whence, lest it should flow down upon the beginnings of the Nerves, by a restraining Membrane it is compelled into the hole of the strait Den lying under the orbicular Prominences; and from thence is received from the declining aperture of the Tunnel, and carried out.

Below the Cerebel, the oblong Marrow going forward with the rest of its tract even to the hole of the hinder part of the Head, ends at length in the spinal Marrow: but in its Trunk, as yet contained within the Skull, besides the Nerves and Processes but now recited, the beginnings of the ninth and tenth pair of Nerves are also radicated. Of what there will be hereafter a proper place to speak, when we shall institute the whole Neurology or the Doctrine of the Nerves. In the mean time, we shall take notice of the beginning of the ninth pair, which is peculiar in Man, and different from what is found in Brutes: To wit, in Man below the origine of the eight pair, a certain Protuberance grows to either side of the ob∣long Marrow. Out of that four or five distinct Fibres do come forth; one or two of which binds about the Vertebral Artery passing through it, but all grow together into the same Trunk, which is the Nerve of the aforesaid pair. This Protuberance, the Pia Mater being pulled away, may be easily seen, and seems to be the Repository or Store-house of the Spirits destinated to this Nerve.

For as this Nerve is bestowed on the Tongue and its Mufcles, and so conduces chiefly to the perform∣ing of speech in Man, who hath a greater and more frequent use and exercise of the voice, there seems to be need of a great provision of Spirits, plenty of which ought always to be in a readiness. But in Brutes, who have none, or a rarer necessity of the voice, such a Protuberance is wanting, because it is not requi∣red in them that the Spirits should be gathered together by heaps, as it were in a certain Porch, before the Organs of the Voice, but that it may suffice for them to be called forth by degrees out of the com∣mon tract of the oblong Marrow. Further, whereas some fibres of this Nerve bind about either Vertebral Artery, unless I am deceived, that is so ordained for this end, lest perhaps in speaking, when at any time we are more vehemently moved, the blood being stirred up, might rush upon the Brain with a torrent. For this Nerve binding about the Vertebral Artery, as it were with a bridle, and so as a Moderator not only of the Tongue, but also of the Blood, restrains its more rapid influence. After the same manner, and for no other ends do recurrent Nerves, destinated to some part of the same office, variously bind about the Trunk of the great Artery, as shall be shewn afterwards.

As soon as this inferior portion of the oblong Marrow is uncloathed from the Pia Mater, the pyra∣midal bodies come in a view otherwise lying hid. These in all Animals, endued with the annular Pro∣tuberance, are constantly found; also as that Protuberance is bigger, so these bodies appear more noted: but indeed in a Man and a Dog they seem like two large Nerves, which being produced out of that Ring, end over against where the eighth pair arise in sharp points. If the use of these be sought into, it is most likely, that the animal Spirits superabounding in the annular provision or store, do flow out as it were by these Emissaries, which Spirits however run into the beginnings of the eighth pair placed near, and so are bestowed by their proper means on the offices of the involuntary Function.

Although the oblong Marrow retains not its name beyond the limits of the Skull; yet it is the same substance, which from thence being continued further into the cavity and utmost recesses of the whole Spine or Back-bone, is called the Spinal Marrow: but it is brought forth for this, that the Nerves to be distributed into the Limbs and Members more remote from the Head, might more commodioufly arise out of the same medullar substance stretched out into the neighbourhood of every part. Indeed all this whole medullar Trunk, which is continued from the bottom of the Brain even to the Os sacrum, seems like the Pneumatick Chest, or Bellows of a pair of Organs, which includes the blast or breath destinated to every Pipe; for in like manner the animal Spirits are contained in this marrowy tract, which blow up and actuate all the Nerves hanging thereto, as occasion serves.

If you behold the origine of the whole, it seems that the whole frame both of this oblong Marrow and the spinal, is of a medullar or marrowy substance, every where growing dispersedly through the Brain and Cerebel, and then being gathered more round together in the middle of either, becomes as an heap. For the Marrows besmearing all their folds and turnings about, are as so many little rivers, which springing from thence, begin to be congregated in the middle, and to be poured out in one great one; but being from thence united, they make the oblong Marrow, as it were the chanel of the Sea, big enough for the motion or ebbing and flowing and reciprocation of the animal Spirits: which belly or chanel, however stretching it self further beyond the Skull, is increased into the spinal Marrow, as it were the bo∣som or process of the former.

But as the medullar tracts, besmearing the folds and convolutions of the Brain and Cerebel, unfold themselves into their middle Marrows and medullar Trunk, and so the Spirits springing dispersedly from their first fountains, congregate as it were into a certain diffused Sea; so from this Sea, causing an ebb∣ing and flowing, or a continual or very frequent influence of the animal Spirit, the same Spirits flow out into the depending chanels of the nervous System.

Concerning this part of this Marrow, which being included in the long bosom or chanel of the 〈◊〉〈◊〉 or Back-bone, and according to all their joyntings, being marked with as it were knotty processes, is called the Spinal, there occur not many things worthy consideration, besides what are commonly known. The figure, situation, as also the body of this, in its whole tract, are known generally to be cloven in two, not only by Anatomists, but by every Butcher. The ramifications or branchings of the Nerves, proceed∣ing from the spinal Marrow, are delivered hereafter. Concerning its conformation something peculiar occurs. For as the spinal Marrow is as it were the common passage or chanel of the Spirits flowing out of the Head into the Nerves, it may be observed, that this chanel, not after the usual manner of other passages, where many rivers flow in, doth swell up more; but on the contrary, in what place it hath more and greater Emissaries, its magnitude is increased; for in those parts of the spinal Marrow, out of which the brachial and crural Nerves arise, (or those Nerves belonging to the Arms and Legs, whose beginnings are more and larger) its Trunk becomes much thicker than in the rest of the frame or substance. The rea∣son of this is, because within the medullar tracts the animal Spirits run not, nor pass through with so swift a passage, but for the most part flowing leisurely from their Fountains, when they have filled the whole space, they stay therein; and as many Spirits, upon occasion offered, are wont to be bestowed on every work, those remaining there in readiness frame certain convenient Promptuaries where they may divert themselves. Wherefore we ordinarily observed, not only of this Marrow, but of the Nerves themselves, that as often as a small branch is distributed into many shoots or suckers to be sent forth here and there, always in the very knot of the division there grows a far greater fold than in the rest of the Trunk of the Nerve; so that 'tis a wonder from whence the Nerve should acquire so in the middle of its passage a new substance and more ample bulk. But of these things and others belonging to the Doctrine of the Nerves, it behoves us to discourse in the following Chapters.

CHAP. XIX. Of the Nervous System in general, where its parts (which are the Nerves and Fibres) being designed, a prospect of the whole Animal Goverment is exhibited.

WHen as hitherto having beheld the several Regions of the Brain it self, the Cerebel, and medul∣lar Appendix, and the provision and offices of them all, we have designed or drawn forth the uses and employments also of the parts and processes, and the sanguiferous Vessels belonging to every one of these; it is now time for me to stop and retire into the Port from this trouble∣som and intricate Sea of Disquisition: But indeed, because I find that I have not yet reached to the farthest shores and utmost parts, but that beyond this Sea, which we have sailed through, as yet the nervous System, and very many Creeks or Bosoms, Meanders, and highly intricate Recesses or private places in it remain to be viewed; therefore although we know it is difficult to proceed with full Sail, we have re∣solved to undertake the task of the Doctrine of the Nerves; and the rather, because without the perfect knowledge of the Nerves, the Doctrine of the Brain and its Appendix would be left wholly lame and imperfect; for neither what hath already been delivered concerning them can be sufficiently undestood or illustrated, nor (which I chiefly desire, and is the end of the former Disquisitions) without those things before known can the Pathology of the Brain and nervous stock be rightly instituted. And indeed there are many things which might easily deter any one from such an undertaking: to wit, the hardness of the work, and full of hazard; which promises at first-sight more difficulty and thorny labour, than pleasure or profit. Then some will object, that this Province is already so perfectly cultivated, and adorned by former Anatomists, that by a repetiton of the same, I may seem to have medled with a thing done to my hand. But I may readily answer to these, first, That the Anatomy of the Nerves yields more pleasant and profi∣table Speculations, than the Theory of any parts besides in the animated Body: for from hence the true and genuine Reasons are drawn of very many Actions and Passions that are wont to happen in our Body, which otherwise seem most difficult and unexplicable; and no less from this Fountain the hidden Causes of Diseases and their Symptoms, which commonly areas•…•…ribed to the Incantations of Witches, may be found out and clearly laid open. But as to our Observations about the Nerves, from our following Discourse it will plainly appear, that I have nor trod the paths or footsteps of others, nor repeateed what hath been before told.

Therefore, that according to our determination we may enter upon the explanation of the nervous System, we shall comprehend under this name all parts, upon which giftcd with the animal Spirit, Moti∣on and Sense necessarily and immediately depend, to wit, for the performing either one only, or both to∣gether in the whole Body. But these kind of parts, in respect of the Head and marrowy Appendix, are like a branching stock or imps growing out of the trunk of a Tree: for supposing that the cortical sub∣stances of the Brain and Cerebel are in the place of roots, and that the substances every where medullar are taken for the stock or pith; the nervous germination or budding forth expanded into divarications of Nerves and Fibres, will appear like so many little branches, twigs, and leaves. Or if the Head contain∣ing in it self the chief part and power of the sensitive Soul, be taken for the body of some Luminary, as of the Sun or a Star; the nervous System shall be that radiant or beamy concretion compassing it about. Because the animal Spirits flowing from the Brain and Cerebel, with the medullar Appendix of either, as it were from a double Luminary, irradiate the nervous System, and so constitute its several parts, the Organs of Motion or Sense, or of both together, as hath been said.

The parts of the nervous System, as a radiant or beamy texture, are either primary, viz. the bodies themselves of the Nerves, into which the animal Spirits immediately flow from the Head and its me∣dullar Appendix; or secondarily, which are Fibres planted or interwoven in the Membranes, mus∣culous Flesh, Tendons, and some of the Parenchyma, which also contain in themselves animal Spirits; but they receive them not but mediately and secondarily derived from the Head through the bodies of the Nerves.

We have already shewed that the animal Spirits are procreated only in the Brain and Cerebel, from which they continually springing forth, inspire and fill full the medullar Trunk: (like the Chest of a musical Organ, which receives the wind to be blown into all the Pipes) but those Spirits being carried from thence into the Nerves, as into so many Pipes hanging to the same, blow them up and actuate them with a full influence; then what flow over or a bound from the Nerves, enter the Fibres dispersed every where in the Membranes, Muscles, and other parts, and so impart to those bodies, in which the nervous Fibres are interwoven, a motive and sensitive or feeling force. And •…•…hese Spirits of every part are called Implanted, forasmuch as they flow not within the Nerves, as the former, with a perpetual flood; but being something more stable and constant, stay longer in the subject bodies; and only as occasion serves, viz. according to the impressions inwardly received from the Nerves, or impressed outwardly by the objects, are ordained into divers stretchings or carryings out for the effecting of motion or sense either of this or that manner or kind.

Indeed the animal Spirits flowing within the Nerves with a living Spring, like Rivers from a perpe∣tual Fountain, do not stagnate or stand still, but sliding forth with a continual course, are ever supplied and kept full with a new influence from the Fountain. In the mean time, the Spirits in the rest of the ner∣vous kind, especially those abounding in the Membranes and musculous stock, are like Ponds and Lakes of Waters lately diffused from the chanels of Rivers, whose waters standing still are not much moved of their own accord; but being agitated by things cast into them, or by the blasts of winds, conceive divers sorts of fluctuations.

But because there is no light difference between the motions and consistency of the Spirits and of Waters, perhaps it will better illustrate the matter, if the Spirits of either kind, to wit, the inflowing and im∣planted, are compared to the beaming forth of divers rays of light. And so when light is let into a dark chamber, and presently inlightens the whole, we may c•…•…nceive the particles of the light so swiftly diffused to be of a twofold kind; to wit, some are bodies sent from the light it self, which diffuse themselves every way into an Orb; and other luminous particles are as it were Etherial little bodies existing before in the pores of the Air, which being agitated by the former, and as it were inkindled, cause as it were a flamy, though most thin contexture, stretched out in the whole clearness. After the like manner, the animal Spirits flowing from the medullar substance into the Nerves, are as it were rays diffused from the light it self, and the other Spirits every where abounding in the Fibres, are as so many lucid particles included and implanted in the Air, which are actuated by the former, and being stirred up by them into motion, perform the acts both of the sensitive and locomotive Faculty.

That it may better appear by what means the animal Spirits do irradiate and swiftly pass through the parts of the nervous System, both primary and secondary; so that light is scarcely carried swifter through a diaphanous Medium, than the communication of the Spirits is made from one end of the nervous Sys∣tem to the other; it will be requisite to inquire here a little concerning the Origine of the Nerves and nervous Fibres, also of their Fabrick and Conformation, to wit, what pores and passages either of these bodies have, and how disposed for the passing through and commerce of the animal Spi∣rits.

As to the Nerves, it is manifest from what hath been said, that all of them are produced immediately out of the medullar Trunk or its processes; so that as these parts are the common and broad roads which lead both from the Brain and from the Cerebel, all the Nerves are particular paths reaching out from them on every side into the several Regions of the animated Body. Wherefore the same Marrow, which is the original of every Nerve or Sinew, foras•…•…uch as it is drawn into a more thin thread, consti∣tutes the matter of the same Nerve; which indeed, that it may be made more solid and compact, is cloathed with a peculiar production of the Pia Matcr, for as from a Silver mass gilt or inriched with

Gold, all the threads produced from it are gilded; so the same Membrane, which covers the medullar Trunk, is produced to gether with all the Nerves coming out from the same, and cloathes them all. Fur∣ther, very many Nerves arising together out of that marrowy beginning, go forth as it were by bands; which notwithstanding, for the sake of the better passage, being presently united and carried out of their bony Cloister, are included in a common Coat taken from the Dura Mater. For we suppose (which also shall be more clearly shewed anon) that all the Nerves, destinated to any parts or every particular mem∣ber, do arise distinctly and apart, and so remain in their whole passage. But in that oftentimes a Nerve appearing as it were one Trunk, afterwards seems to go into many branches, it is because those branches being indeed singular, and divided in the whole passage, are collected as it were into one bundle; for sometimes we have separated those Nerves, seeming to grow together as it were into one rope or cord of of a Nerve, one from another, dividing them to their very original; for neither otherwise could the In∣stincts of the Motions to be performed be carried so respectively to these or those parts, separate one from another, to which the branches of the same Trunk belong.

The passages of the Nerves are not bored through as the Veins and Arteries; for the substance of those are not only impervious to any Bodkin, but no cavity can be seen in them, no not by the help of Specta∣cles or a Microscope. As to what belongs to the smelling little Pipes, they seem to be so made, not for the passage of the animal Spirits, but that some serosities might slide down that way: but the Spirits them∣selves are carried in the sides, and not in the cavity of either Pipe; but the substance of the other Nerves appears plainly firm and compacted, that the subtil humor, which is the Vehicle of the Spirits, may pass through their frames or substances, even as the spirits of Wine, the extended strings of a Lute, only by creeping leisurely through. Hence it may be argued, that because the animal Spirits require no manifest cavity within the Nerves for their expansions; neither is there need of the like for them within the substance of the Brain; but that the Ventricles, commonly so called, ought to be deputed to some other office than this.

But the Nerves are white, smooth, and round bodies: within the Skull and nigh their beginnings, being as it were only covered with the Pia Mater, they are soft and easily broken; without this, for that many of them are for the most part gathered together, and also cloathed with the Dura Mater, they become somewhat hard and more tenacious. The Nerves themselves (as may be discovered by the help of a Microcosm or Perspective-glass) are furnished throughout with the pores and passages, as it were so ma∣ny little holes in a Honey-comb, thickly set, made hollow, and contiguous one by another; so the Tube∣like substance of them, like an Indian Cane, is every where porous and pervious. Within these little spaces the animal Spirits or very subtil little Bodies, and of their own nature ever in a readiness for motion, do gently flow; to which is joyned, both for a Vehicle, as also for a Bridle or stay, a watry Latex, and that it self of very subtil parts. This Humor diffuses, with its fluidity the Spirits through the whole nervous System; also by its viscosity retains them, that they be not wholly dissipated, but as it were in a certain Systasis and continued Series; for it seems, that without such an Humor the Spirits could not consist within the nervous stock, but they would vanish away into Air. Further, the same Humor is no less re∣quired for the passing through of the sensible Species: because the animal Spirits, we suppose, like the rays of Light, to be diffused through the whole nervous System; and those rays, unless the humid particles of the Air be mingled with them, do not easily transmit the forms or images of things; as is obvious in an Optick Scene, which is hid or shadowed by the clear beams or brightness of the Sun. And in like manner, from the defect or depravation of the nervous Juyce, we can readily shew, that the inordinations of the animal Spirits, and oftentimes most horrid distempers of the Brain and the nervous stock do arise.

This nervous Juyce being derived from the Brain and Cerebel into the medullar Appendix, is carried from thence by a gentle sliding down through the Nerves even into the whole nervous stock, and waters its whole System. Upon the equal emanation of this depends the expansion of the animal Spirits through the whole; and the substance of these, yea the Hypostasis of the sensitive Soul it self is founded on the diffu∣sion of the same humor. The animal Spirits being lest to themselves, follow the motion of this Juyce, and flowing together with it in the same course, are pleasingly or quietly expatiated; but in the mean time, as occasion is offered, the same Spirits, as a breath moving upon those waters, conceive other spreadings abroad, and those more rapid. For as in a River, from winds or any thing cast in, divers undulations or wavings are stirred up; so the animal Spirits being raised up by objects, for the performing the offices of sense and motion, do tend this way or that way to and fro within the nervous stock, and are agitated hither and thither by other means.

But to return to the parts of the nervous System, besides the Nerves themselves, Fibres also being dis∣persedly interwoven in the Membranes, the musculous Flesh, the Parenchyma, and other parts, and uni∣ted in the Tendons, are the Organs of sense and motion. Yea, the acts of their faculties are principally and more immediately executed by the Fibres than the Nerves; for they, by drawing together the Muf∣cle and other motive parts, cause the motion it self; but the Nerves only carry from the Head the in∣stinct for the performing of that motion. In like manner, in Sensation the Fibres receive first of all and immediately the impressions of sensible things, and express the same (as musical strings do the strikings of a quill or fingers) by an intrinsecal modification of the Particles, and represent the various approaches of the object by the like motion of the Fibrils, as by a moveable and fluid Character, whose Idea the Nerves transfer only to the Head.

Concerning the nervous Fibres it behoves us to inquire from whence they have their rise? For it ap∣pears plainly, that they arise not immediately from the Head or its medullar Appendix; not is it less im∣probable, that they are produced (as 'tis commonly said) from the Nerves: because what is asserted, that the Fibres are productions of the Nerves, and little bits or pieces of them torn off, as it were into hairy branches, seems unlikely; for that the Fibres in some parts, being placed nigh, exceed in their bulk the magnitude of the Nerve that is brought to that part, at least an hundred-fold: which thing appears clearly from the Tendon of every Muscle, which being made up of united Fibres, is observed to be far greater than the Nerve inserted to it. And indeed for almost the like reason we are induced to think the nervous Humor it self also, whereby the Membranes and musculous Fibres are wont to be watered, to be deri∣ved unto them not by the only means and passage of the Nerves; because it is heaped up much more plen∣tifully and in more abundance than can be carried thither through those narrow passages, as appears clear∣ly in Ulcers of the Kings-Evil, or in Impostumes or Wounds of the Tendons and nervous parts, in which a glutinous Humor drops forth in so great abundance, that all the Nerves of the whole Body could scarce be able to supply it.

Wherefore concerning these, it seems that we may affirm, that the Fibres are not continued portions of the Nerves broken off into little hairy strings or Capillaments; and that all the Fibres originally proceed not from the Nerves, because some of them, viz. those interwoven to the Heart and its Vessels are of e∣qual birth with the Nerves themselves, and coexist with them together from the beginning. However the most Fibres, as to their production, depend upon the Nerves; and all, which way soever brought forth, receive constantly from the Nerves the forces and supplements of the animal Spirits, and also Instincts of the Motions to be performed by them.

Therefore to recount the births or kinds of Fibres; they are first either spermatick and first begotten, the rudiments or first beginnings of which being of the like antiquity as the Heart and Brain, placed in the Conception, afterwards leisurely increase; to wit, such are, as hath been said, those in the Heart it self in its depending Vessels, the Membranes and some other parts, which form the first stuff or threads of the Embryo: or secondly, other Fibres are produced secondarily, and by a second birth; of which sort chiefly are such which are interwoven into the parts taken for the compleating of the animal Fabrick, and especially those termed Sanguineous, which we think to be begotten after this manner.

The Heart and Brain, with the Arteries and Nerves hanging to them, are primigenious parts, and high∣ly original; but these, for the second birth of others, and for the nutrition and increase of all the sensitive parts, distribute a twofold humor: viz. one spirituous and endued with very active Particles which per∣petually flow, though but in a very small quantity, through the passages of the Nerves from the Brain and Cerebel; and the other slow and softer, which being every where laid aside through the Arteries from the bloody mass, is rendred more plentifully. This latter being of it self dull and thicker by much, is actuated by the former, and being imbued by it, as by a certain Ferment, acquires strength and power of growth or vegetation. But indeed the nervous Juyce, forasmuch as it diffuses with it self the animal Spirits, imparts to every part, besides the faculties of Motion and Sense, the determinations also of form and figure. Further, whilst that, being joyned to the other arterious humor, is disposed into the sub∣stance and matter of the member or part to be nourished, it forms some tracts as it were, to wit, the Fi∣bres themselves, in which the animal Spirits, coming together with them, reside and are expatiated. These twofold or twin humors, coupling together in every sensitive part, constitute a liquor truly nutri∣tious, to wit, which is both spirituous and nourishable. And in truth, both these Juyces, viz. the nervous and arterious, being married together, are as it were the male and female seed, which being mingled in a fruitful womb, produces the plastick Humor, by those virtue the living creature is formed and increases. Hence may be observed, as the particles of the spirituous liquor, or of the other more watry juyce (viz. this latter being supplied from the Arteries, or that from the Nerves) are strong or excel, as to their pro∣perties or powers, all living creatures become more or less nimble, active, and ready to any motion and labour. Besides, from the default or depravation of the one and other humor excelling, the sorts or kinds of this or that disease are excited; concerning which, and also what belongs to the explication of the nu∣tritious Humor, we may perhaps have some other time occasion to discourse.

The animal Spirits which enter and fill the ordained series of the Fibres as so many little places, flow thither by the passages of the Nerves, notwithstanding the Spirits which are seated in the Fibres, inter∣woven with the musculous stock, receive nourishment, yea and as it were auxiliary forces, from the arteri∣ous blood there plentifully slowing: whereby indeed both the Spirits themselves acquire for the performing of Motions a greater force and as it were elastick; so that their force being stirred up by a strong endea∣vour, it seems like the explosion of Gun-powder; and also the same Spirits being continually consumed within the Muscles more profusely than is wont to be in the Membranes and other parts, are in some measure made up or repaired from the bloody sustenance: because whenas the arterious Juyce joyns more plentifully with the nervous flowing within the sanguineous parts, it may be well thought, that it also lays upon the Spirits brought thither with it, as it were some nitrosulphureous particles, and intimately fixes them on them; and so, by reason of this Copula, highly flatuous and apt to be rarified, the Spirits themselves become there more active, so that in every motive endeavour, whereby the Muscle is suddenly intumified, they, as if inkindled, are exploded. Moreover, a sudden refection of the consumed or wasted Spirits, after great exercise or labour, is for this reason also performed by the blood; for that the spirituou

particles being left and forsaken by motion, presently a new Copula of the same kind of matter, apt for explosion, is joyned to them. For it is not possible, that the immense loss of Spirits which happens in hard labours (if they were wholly destroyed) in so short of time, should be able to be restored by supple∣ments coming only through the Nerves. We shall discourse more largely of these things, if at any time hereafter we shall treat of the Motions of the Muscles.

The animal Spirits being disposed within the several Muscles, according to the series of Fibres, seem as it were so many distinct Troops or Companies of Souldiers; all which being set as it were in a Watch∣tower, are ordained, as a new impression is carried to them by the Nerves, either from the objects out∣wardly, or more inwardly from the Head, forth with into various forms and peculiar orders for the perform∣ing of motion or sense of this or that kind. The carriage or behaviour of these is worth the seeing in an animal newly killed and its skin taken off. For when life perishes, and all the force of the Spirits flowing in through the Nerves hath quite ceased: yet the Spirits implanted into the whole Body breaking forth from the Muscles, still move and shake them, and force them into several Convulsions and trembling motions.

From what hath been said we may gather, what the disposition or order of the animal Spirits may be in the whose animal Body: to wit, those procreated in the cortical substance both of the Brain and Cere∣bel, are congregated in to the middles of either, as it were into distinct Empories or Marts; and an ex∣pansion being made in either, they cause certain interior powers of the Sensitive Soul to be exercised; yet the same Spirits, affecting more room, enter the oblong Marrow (as it were the Chest, as hath been said, of a musical Organ) and fill it full; within which flowing, they carry to and fro the impressions of sen∣sible Things and the Instincts of Motions. From the oblong and spinal Marrow the same Spirits, unless when they are otherwise busied, tending outwardly, flow towards the several parts of the whole Body; which notwithstanding wandring so out of doors, because they pass through very strait ways in their pas∣sage, to wit, the slender bodies of the Nerves, they break not forth in heaps, or in a thick troop, but only contracted orderly, and as is were by bands or divisions: but they being carried beyond the extremities of the Nerves, and there possessing the Membranes, Muscles, and other sensible parts, dilate them∣selves as it were into a most ample field, and with a very diffuse Army they dwell in the Pores and passages of the Fibres planted every where about; where also being endowed from the blood with new food, they become more lively and more expeditious or ready for the designed offices.

Here perhaps it may be demanded, how the animal Spirits, diffused in such numerous troops through the habit of the Body, are able to be supplied by so strait chanels of the Nerves? To which we reply, That those which reside more outwardly do not quickly evaporate, nor are remanded back by Circulation: wherefore when all the Fibres are filled by an influx of the Spirits made by little from the beginning, very small supplements suffice to repair their expence: For neither are those dwelling more outwardly, for that they are repaired by the bloody food, much consumed, though in frequent action.

Hence may be noted the difference between the distributions of the blood and animal Spirits. That Latex, because it is reduced in a circle, its Vessels are in the whole passage proportionated as to the bulk of the Trunk and the branchings sent from it, to wit, so that the branches of the great Artery, being carried from the Heart, contain at the least so much of the blood, as the shoots reaching forth from them, into all the parts. But because the animal Spirits being once begotten and carried more outwardly, subfilt longer there, and evaporate very slowly and by little and little; therefore the Vessels carrying them, viz. the Nerves, in respect of the Fibres receiving rhem, are made much lesser in proportion; lest perhaps by too great a supplement of the animal Spirits, and the too thick gathering of the fresh ones still into the ner∣vous parts, the Army of the Veterans, before instructed, should be confounded, and so the orders of all be∣ing disturbed, the exercises of the animal Function should be performed any now. For indeed when at any time the Spirits are made too sharp, so that. being therefore struck as it were with madness, they rush upon the nervous System with tumult and impetuosity; from hence a great unquietness and continual throwing about of the Members are wont to be excited, to which sometimes madness and fury succeed.

In the order and ordination of the animal Spirits, such as was but now described, the Hypostasis or the Essence of the sensitive Souls consists to wit, which is only a certain Systasis or shadowy subsistence of those Spirits, which like Atoms or subtil Particles, being chained and abhering mutually one to another, are figured together in a certain Species. Moreover, the faculties of the same Soul depend upon the va∣rious Metathesis and gesticulation of those Spirits within the aforesaid Organs of the Head and nervous System. But the consideration of this Soul and its powers requires a peculiar Tract, which hereafter (God willing) we intend; in the mean time, our Method demands of us, that (accorging to our weak skill) by the cense or numbering of the Nerves, being particularly made, we should deliver an exact Neurology or Doctrine of the Nerves.

But for that in the premised general consideration of the Nerves and Fibres, there was mention made of the nervous and nutritious Juyce; notwithstanding what belongs to their powers and natures, hath been neither fully nor clearly enough delivered; therefore we will a little divert here, and make it our business to inquire what sort of Juyces and Humors are carried into the parts of the animated body for their nourishment, and by what ways or passages: then this difficulty being removed, a plain and easie way leads into the Doctrine of the Nerves.

CHAP. XX. Of the Nervous Liquor, and whether that or the bloody Humor be Nutritious:

SInce the Circulation of the Blood was made known, and it hath been plainly made appear, that it did no where stagnate and stand still long, but was carried in a reciprocal motion, always as in a circle; it began to grow doubtful, whether its Latex is nutritious or not. For besides, that the more rapid course of the blood, as of a torrent, might seem to wear the banks which it flowed be∣tween, and to carry away some Particles from them, rather than to be able to affix any thing to them; the substance it self also of the blood, for that it is more torrid and uneven, is thought to be altogether unfit for nutrition. Wherefore that a Juyce may be found more convenient or fit for this office, the passages and hidden recesses of the Nerves are to be viewed; and as a certain Latex is found to flow within their Pores and passages, presently the blood being rejected, that nervous humor is gifted with the title of nu∣tritious: but yet by what right, and after what manner nutrition is performed, shall be our present pur∣pose to inquire.

And here first of all, that we may take the part of the blood, it will be easie to shew, that there is mat∣ter contained in it fit enough for the nourishment of the body, and a sufficient store of it. For besides the sulphureous substance of the blood, which within the fire place of the Heart, with a continual inkindling, and by that means deflagration in the Vessels produces life, and in the more perfect Animals heat, there is found also a certain other humor soft and alible, which in the Circulation, being distributed through se∣veral parts of the Body, by increasing them adds nourishment and bulk: yea the deflagration it self of the blood, plainly as a Kitchin-fire in dressing meat, as it were boils and prepares this humor, whereby it more easily is assimilated into the substance of every part to be nourished. Hence it comes to pass, that by reason of a defect of heat in the blood, no less than of excess, nutrition is often hindered. But that this kind of alible Juyce is contained in the blood mass, the Anatomy or spontaneous Analysis of its Latex suf∣ficiently declares; for the extravasated blood, when it goes into parts of its own accord, this liquor being disjoyned from the purple thick part, and swimming a top of it, appears clear or limpid; but by reason of its more thick contents, to wit, the nutritious Particles, like the white of an Egg, it is easily made thick, and grows white by a gentle heat: which thing appears by this familiar Experiment, to wit, if you shall evaporate a little of it only in a Skillet over the fire, the whole liquor will presently grow together into a white Gelly. By this liquor, as the blood is more or less imbued with it, living Creatures grow and become more fleshy or lean: for both the blood of younger Animals being loosned from cold, is wont to shew much more of this kind of white than more ancient or older Creatures: and we may take notice daily at our Tables, that very much of this kind of Gelly comes out of the flesh of a Lamb or Calf being boiled or roasted, and nothing almost from Mutton or Beef, especially if old. Therefore we may lawfully suppose, that the blood is truly nourishable; and that the whole, or at least the greatest part of the matter, for the adding bulk or substance to every part, is dispensed from it: but if at any time it be defective in this its office, that happens not out of the natural unfitness of it, but because its disposition is sometimes depraved, and as the Stomach labouring with some vice, rejects or perverts the Chyle to be cooked by it.

But the blood, as it is not the only and alone humor, which is distributed in the animated Body, so nei∣ther seems it able to perform alone and of it self the whole office of nutrition. For besides that, being diffused through the Arteries and Veins, another Latex is every where dispensed from the Head through the Nerves; which shall be shewn to afford something at least to nourishment.

As to the first, there are many reasons which declare that kind of humor to be in the Brain and ner∣vous stock, and to abound in their whole passages. For unless the animal Spirits, continually flowing out, should be founded in such a Latex, which is their Vehicle, they would not be contiguous or joyned, nor able to continue and knit together the Systasis of the sensitive Soul. For if Hipocrates did observe long since, that Cramps and Convulsive motions were produced from driness and emprines, that perhaps might happen by this means: to wit, because humor in the Nerves or Fibres being deficient, the Spirits distracted one from another, were separated; which notwithstanding, that they might still retain their mutual embraces, and as it were folding of hands, bend the containing bodies, and very much contract and so force them into Convulsions. Besides, Wounds and Impostumes of the Tendous and nervous part seem to witness the diffusion of the nervous Juyce, either of which drop forth a thin Ichor, and wholly unlike to the mere bloody Excretion: no less may be argued from the Ganglia and evil running Sores. In time of sleeping the aforesaid humor is wont to flow more plentifully into the Brain and Nerves, and to obstruct their passages; and therefore yawnings and stretchings come frequently upon those awaking, that its reliques might be shook off. Lastly, we might readily shew, that from the depravation of

the nervous humor, Melancholy, Madness, and some wonderful Convulsive distempers proceed. But it may be objected, that there is no such kind of humor, because the Nerves being cut asunder, it is not perceived to flow out; and that the Nerves being also bound, they do not swell above the Ligature, as Arteries and Veins. But it may be answered, That the liquor flowing in the nervous stock, is very subtil and spirituous, and which, by any striving or wrinkling up of those parts, when they are roughly handled, may easily evaporate and be blown away or dispersed unperceivably. Then further, tis observ∣ed in the Whelps of some Animals newly litter'd, who have as yet that juyce viscous, and not easily to be dispersed, and that have their Nerves greater, if they be bound hard together with cords they will swell above the Ligature.

Therefore seeing it appears, that a certain Humor doth creep through the blind Pipes and passages of the Head and of the Appendix, both medullar and nervous, it behoves us next of all to inquire from whence that comes thither, and whither it tends; and lastly, of what kind of nature and use it is. Con∣cerning these first it appears, from what hath been said, that the aforesaid Latex, serving for a Vehicle of the animal Spirits, is perpetually instilled, together with them, from the blood watering the exterior con∣fines of the Brain and Cerebel, which from thence, passing through the medullar Trunk, is afterwards, with a gentle spring, poured through the whole frame of the nervous System; so that the first fountains of the nervous humor are in the Brain and Cerebel. But further, to this Juyce conveying the forces of the animal Spirits, and supplied only from the Head, there joyns a certain other humor, as it were auxiliar in the whole passage, and restores and refreshes it otherwise about to grow deficient.

We think that these kind of supplements and subsidies, which happen to come from elsewhere to the nervous Juyce flowing from the Head, are received and addmitted inwardly from the sides and extremi∣ties of the medullar and nervous System. We have already shewed that an humor, as it were secondary, is instilled from the blood watering these parts in its whole passage; because the Arteries follow out only the medullar Trunk, but also the greater Trunks of the Nerves in many places, and insert into them sanguiferous shoots. Besides, forasmuch as the animal Spirits flowing within the nervous stock for the performing of sense and motion, tend to and fro, and so bear a double aspect; it is probable also, that the liquor watering the Nerves, as it most commonly tends forward, so sometimes backward; and so that the extremities of the Nerves, implanted in some parts, imbibe from them the humor, at least some Efflu∣via's, with which they are satisfied, and oftentimes transfer them into the Brain it self. Certainly there is no doubt, that the Fibres and nervous Filaments or threads which cover the Sensory of taste, and the Vis∣cera serving for Concoction, do immediately receive some tastes of the taken in food, from which sup∣plies are carried to the Brain it self in great hunger and faintness of Spirits. Because if at any time the Spirits inhabiting it, being exhausted very much with heavy and long labour, begin to fail, a most swift refection is performed, Pectorals or Cordials being scarcely swallowed, and long indeed before the alible Juyce can be able to reach to the border of the Brain by the passage of the blood. Moreover it is most likely, that not only the benign Effluvia's of the aliment are received by the extremities of the Nerves ending about the Viscera; but also by this way, that oftentimes an infestous matter, and in a manner ma∣lignant, is communicated by the Nerves and their passages to the Head. But indeed the preternatural Juyces heaped up about the Hypochondria, the Spleen, Womb, and other Bowels emit vaporous little bo∣dies; which not only infect the bloody mass, and distemper the Head by that means, but they climb to the Brain more immediately by the passage of the Nerves, and strike it with an heavy ill. For from hence in part it comes, that Hypochondriacks and Hysterical people are so cruelly punished through the Symptoms stirred up in the Brain and nervous stock for the faults of the lower Bowels; hence it is, that little Pills of Opium, being scarcely dissolved in the Stomach, cause a Torpor or heaviness. But here is no place to discourse more largely of these. It behoves us to consider what remains, the Springs of the ner∣vous Juyce, the Auxiliaries but now detected, and its Virtues and influences.

Concerning the nervous Liquor we shall inquire what that doth in its passage, to wit, whilst it flows within the Marrows or middle of the Brain and Cerebel, the medullar Trunk and the bodies themselves of the Nerves: secondly, then for what uses it serves, when being sliden from the ends of the Nerves, it is spread abroad on the secondary parts of the nervous System.

1. As to the first, whilst that of the nervous Liquor passes through the Head, and either of its Appen∣dix, its chief office seems to be for a Vehicle of the animal Spirits, which indeed it carries along with its diffusion, and contains them under the same Systasis. Yea, this Latex shews various Schemes of the Spirits for the performing of sense and motion; even as the humid Particles of the Air pass through the Optick Configurations of the Rays of Light. Also moreover, the nutrition of the aforesaid part and accretion or growth into a bulk, depends in some measure upon the nervous Juyce watering the same, as shall be shewed by and by.

2. But the greatest question is concerning this Liquor being diffused beyond the ends of the Nerves upon the secondary parts of the nervous System, and in the passages of them on the whole Body; to wit, whether such a Juyce be nourishing of all the solid parts, or of some of them by themselves, as Authors va∣riously think; or to what other office it is destinated.

Concerning these it first appears, that the Brain and Nerves, with the Juyce flowing out of them, contribute matter, or at least some influence to the work of nutrition; the which if it should chance to fail (a sign of which defect is, if the animal Faculty falters in part) the nourishment there is wont presently to be hindred or perverted. This is plainly seen in the Palsie, excited from an evident cause, without any previous Dyscrasie of the blood, where suddenly an Atrophy follows the privation of motion or sense, or of both together. Further, in the Scurvy, where the taint hath corrupted the nervous Juyce, when the sick begin to be afflicted with the Vertego and swimming of the Head, and with wandring pains, Con∣vulsions, and a frequent loosning of the Members, the flesh falls presently away, as in a Consumption, and without any fault of the Lungs, the sick wither away, as if distempered with a Phthisis. It is a vul∣gar observation, That from the immoderate use of Venus, also from an inverate Gonorrhoea, from Stru∣mous or running Ulcers, and other Impostumes, by which much of the nervous Juyce is wasted, a leanness or wasting of the whole Body is produced. Certainly, if I be not deceived, there are some Atrophies, yea, and sorts of breakings out, which seem to depend wholly upon the detect or the evil dispensation of the nervous Juyce, when the blood, as to its quantity and disposition, is not much in fault. Lastly, the consideration of some Diseases and Symptoms so plainly confirms the diffusion of the nervous Liquor and its great influence on all the parts, that there is even left no room for doubting.

Also no less doth the curing of some Diseases and the use of Remedies confirm the same. For from hence a reason is taken, wherefore Cephalick Plasters oftentimes yield such signal help in the Phthisis; not because they stay the Catarrh of the Serum falling down on the Lungs, (as the common people think) but because by corroborating the Brain they restore the disposition of the nervous Juyce, before vitiated. For this cause it is, that some diseases being stirred up by the fault of the nervous Liquor, of which sort a∣mong others are Cancrous and Strumous Ulcers, or such as come of the Kings-Evil, are hardest of all to be cured; because the morbid tincture of the Brain, and of the Latex watering it (whether it be innate or acquired) is not easily mended: yet sometimes when the root of the disease, lurking in the Brain or nervous stock, is taken away by the help of Nature it self, or by Chance, by the use of some remedy; presently the Symptoms of other parts, though neglected in the whole, vanish, not without the suspicion of a miracle. But how much the alteration of the Brain serves for the curing of some most grievous dis∣eases, some instances taken from the Farriers Art will clearly shew.

For when many Medicines and Methods of Administrations are wont to be tryed in vain for the cur∣ing the stinking disease in Horses, commonly called the Farcy (which Helmontius asserts to be like the French Pox, and the author of its Contagion) the most certain means of curi•…•… (which I have very often known to be applied with good success) consists in this; that some sharp Medicines, of which sort are Hearts∣ease, Water-Pepper, Ranunculus or Crowfoot, and the like, which very much abound in volatile Salt, being bruised into a mass, and put into the Ears of the diseased Horse, and kept there for twenty four hours: it is scarce credible by what means all the Ulcers are presently dryed up, and the disease healed, as it were by Inchantment, is quickly profligated in the whole. For since this Application is made far from the affected parts, without any alteration of the bowels or the blood, it should be so healed at a dis∣tance; certainly the cause of such an Energy must only be, that by this kind of Medicine the Dyscrasie or evil disposition of the Brain and nervous Juyce is taken away, and so the first root of the sickness being cut off, the shoots and fruits presently wither. It were worth our labour to try such kind of Experiments that also in our Medicines. Yea it may be well suspected, that such a way ought to be ordered for the com∣mon Cure of the Kings-Evil. Among our Country-men, as delivered from our Ancestors, it is thought the seventh Son, or he that is born the seventh one after another in a continued series, can cure this dis∣ease by stroking it only with his hand; and truly I have known many, whom no Medicines could help, to have been cured in a short time only by that remedy. Few doubt but that this disease is wont to be cured often by the Touch of our King. The reason of such an effect (if it be merely natural) ought to be assigned not to any other thing than that in the sick (especially those of ripe age) the Phantasie and strong Faith of the hoped for Cure induces that alteration, or rather strengthning to the Brain, whereby the morbid disposition radicated in it is profligated. But I shall return from whence I am digressed, to in∣quire what the nervous Juyce contributes to nutrition.

2. I say therefore secondly, although nutrition depends in some measure upon the influence of the nervous Juyce, yet it is highly improbable, that all the several parts of the whole Body should be nourish∣ed only by this provision. For besides that this, were to impose upon the Government of the Soul it self, and its primary Organs, the cooking office of nutrition wholly unworthy the excellency and dignity of those parts; it seems also that the nervous Liquor should be all together unfit for the administring to this Province: because when oftentimes immense expenses are made of the aliment to be assimilated into the substance of the solid parts, especially by immoderate sweat, also by continual labour and exercise, which Country-men and Labourers daily use, it is not possible that such losses should be repaired only by the nourishment supplied, or sent through the small passages of the Nerves.

When I had long and seriously considered with my self concerning this thing, what I at length thought, I shall tell you freely, and without any covering, or making any reflection, or blaming the O∣pinions of others. It seems first, that the nourishing matter of the whole Body is distributed into all parts from the blood through the Arteries; yet it may lawfully be thought, that the conversion of this matter into nutriment, and the assimulation of it into the substance of the part to be nourished, is performed by

the influence and help of the nervous Juyce, as it were of a certain spirituous Ferment. As to the first: we have already noted, that the sanguiferous Vessels do not only follow almost every where the Muscles and Bowels, but also the Head and its Appendix, yea the Membranes, Bones, and Nerves themselves, and affix to them all thick shoots, as so many little chanels, for the receiving the nourishment. More∣over, as there is a purple crassament or thick substance in the blood, whose substance stuffs and nourishes the Pores of the Parenchyma of the Muscles; so there is a whitish Gelly, by which the Membranes and the whiter parts seem to increase. Besides it may be observed, that the blood it self increasing, contains in it self fibres and small threads, such as are interwoven in the Muscles and nervous parts; and if the same stand long in any Vessel, it is presently coagulated into longish, white, and hard crusts or bits, whose substance is plainly fleshy; so that the blood produces flesh of it self, though the same be rude and unformed: wherefore the configuration and the apt disposition of the nourishingmatter, supplied from it, depends on the coming and Energy of the nervous Juyce: but after what manner this is done, we shall endeavour now to shew.

After the web or stuff of all the parts is laid, it is required then that they be both drawn forth in due proportion, and grow in substance, and also that the little spaces which are left by reason of the Effluvia's perpetually falling off, may be continually filled with the nourishing substance cast in. In these two things the business of nutrition chiefly consists; for the performing of either of which the blood affords matter, and reaches it forth (as was said) in the circulating to the several parts of the concrete, and as it were stands at the doors of the part to be nourished: yet, that this matter may be rightly disposed, and its particles, to wit, the thick and thin, saline and sulphureous, and others of a several nature, separated one from another, may be imployed with some choice to the destinated uses, there seems need of a certain directing faculty, and as it were plastick virtue, got somewhere else than from the blood it self. For in∣deed the blood being destitute of animal Spirits, is unfit for the performing these offices. Wherefore, for that it appears there doth lye hid in the nervous stock, a certain juyce, and the same being gifted with animal Spirits to be diffused to all parts, how can we suppose less but that this subtil and spirituous Li∣quor, every where meeting with the arterious which is duller and thicker, actuates and inspires it, and as it were ordains it for the performing the designed work of nutrition? especially when it plainly ap∣pears, that by reason of the defect or depravation of this nervous Juyce, nutrition is always frustrated or perverted.

Therefore it may be lawful, in •…•…e difficult Controversie concerning the Matter and Method of Cure, to propose this our Hypothesis, tho•…•…h it be a Paradox and very abstruse; to wit, that the nervous Juyce (which we have said was like the male seed) is poured out with the nutritious humor copiously suggested from the Arteries, as it were the genitive or seed of another Sex, every where upon all the parts; and that this former, being indued with active Elements, imbues the more thick matter, as with a certain Ferment, and impregnates it with animal Spirit; and when it so makes it, with a mutual entring in or coming together, to be dissolved and to go into parts, its particles being extricated one from the other (the Spirit infused helping) they are put upon bodies of the same measure with themselves, and are as∣similated into their substances. In the mean time, because the animal Spirits are poured out in great plenty with the nervous Juyce, those which are at leisure from the work of nutrition, or remain after that is finished, turn aside every where into the Fibres, as into proper dwelling-houses, and there being ready for the offices of sense and motion, stay; which offices indeed, that those Spirits the Inhabitants of the Fibers, may the better perform, they acquire from the blood watering the Muscles, certain auxiliary forces, wherefore they being endued with a certain elastick force, are apt to be highly rarified and as it were exploded.

But indeed we suppose, that as the nervous Liquor, being turgid with animal Spirit, causes the arte∣rious humor to become nutritious; so in compensation of this the animal Spirits remaining of the work of nutrition, and every where disposed within the Fibres, receive from the arterious blood a mixture or certain Copula; by whose help and cooperation the same Spirits exert or put forth much more strongly their locomotive force. For it seems that little sulphureous bodies are added to the spirituous∣saline particles from the watering blood; and so when the animal Spirits are furnished with this Copu∣la, they being stirred up into motion, shake off the borrowed particles, which being struck with a certain force, like the explosion of Gun-powder, suddenly intumifie the Muscles, and so by contracting them very much, they cause a vehement motive endeavour. We shall have an occasion of discoursing more at large of this, when we treat of the Motion of the Muscles.

Yet in the mean time, we shall take notice, that the Muscles of the whole Body, as to their motion, have a certain Analogy with the motion of the Heart. For indeed the animal Spirits in the Heart, flowing within the fibres and nervous threads, (with which this part is much beset) receive plentifully sul∣phureous little bodies from the inflowing blood distending the sides of either bosom, which whilst the same Spirits, being filled to a fulness, shake off and as it were explode, a Systole of the whole Heart (its sides being carried with a certain force inwards) is brought in or caused, whereby the blood, from either side the bosom is cast out as as it were by the impulse of a Spring or Bolt. Truly, unless the Spirits inhabiting the Heart, should receive food and matter of explosion from the blood it self, their stock, supplied or sent by the passage of the few and small Nerves, would not suffice for the performing of the undiscontinued motion. A sign of this is, that from a defect or depravation of the blood, as well as of the animal

Spirits, the motion also of the Heart is defective or diminished. And not much unlike in the Muscles, as in the Heart, is the business performed; the Spirits inhabiting their Fibres, receive a sulphureous Copula and apt for explosion, from the blood there more plentifully flowing than about the Membranes, with which being endued, as often as they receive from the Nerve as it were the fiery inkindling or the match, the in∣stinct of the motion to be performed, they being excited, and striking off their Copula, very much in∣flate or blow up the Muscle, and intumifie it for performing or compassing the motive endeavour. Nor is it much to purpose, o•…•… makes any great difference, that the motion of the Heart, stirred up by a per∣petual instinct, is found always necessary; but the Muscles the most of them only occasionally and at the command of the Animal, do put forth their motive power; for the Diaphragma and some Muscles, dedicated to Respiration, are urged with a perpetual Systole and Diastole, as well as the Heart it self.

From the aforesaid Hypothesis concerning the offices and uses of the nervous and arterious Juyce, Ar∣guments that otherwise determine the work of Nutrition, may be easily answered. For that the blood is said rather to prey upon the solid parts than to replenish them, that ought to be attributed to the Di∣sease and Dyscrasie of it, and not to it simply: because sometimes the blood is accused, for that it too much stuffs the solid parts; to wit, forasmuch as its mass being waterish and weak, it lays aside the alible Juyce (which not being truly cook'd, is still crude and vicious) with very great plenty abou•…•… the habit of the Body, and so induces an Anasarcha. In the mean time it ought to be granted, That as it is the blood that is evil which heaps up too much vicious nutri•…•…ent; so it is the same, which being, well and right, doth laudably perform the office of Nutrition.

But that it is argued, That the nervous is rather the nourishing Juyce, because by reason of its defect, depravation or too prodigal expence, the acts of nutrition are wont to be hindred or perverted; it is ea∣sie to reply to this, That the impediments of the nervous Juyce, being made vicious, respect the form of nourishment, and not the matter of it: to wit, it sometimes happens, that the blood dispenses the ali∣ble matter in due plenty and disposition; which notwithstanding, by the fault of the nervous Juyce, is not rightly assimilated. When an impotency of motion comes upon a too great distension of the Muscle or Tendon with pain, shortly nutrition being hindred, a Jelly grows about the distempered part: which notwithstanding drops not out of the Nerve (as is commonly said) but the glutinous hu∣mor being poured out of the Arteries for aliment, for that it cannot be received by the hurt part, is ga∣thered together there: nor is it to be thought, that Tumors, or Strumous Ulcers or the running Sores of the Evil do contain or pour out only a nervous humor, since the matter of either is for the most part bloody, which by reason of the evil Ferment of the nervous Juyce, puts on a strange form, and that di∣versly degenerous.

This supposition of the twofold Humor, for the matter and form of nourishment, is taken to be of egregious use for the solving of the most difficult Phaenomena, which are met with about the Distempers of the Brain and nervous Juyce: yea that Pathology, seriously considered, seems to infer as a certai•…•… ne∣cessary consequence, that a twofold Juyce is necessary for the work of nutrition; as some other time per∣haps we may shew. In the mean time, leaving this Speculation, we shall proceed to the remaining Task of our Anatomy, to wit, the Neurologie or of the Nerves in particular.