The remaining medical works of that famous and renowned physician Dr. Thomas Willis ...: Viz I. Of fermentation, II. Of feavours, III. Of urines, IV. Of the ascension of the bloud, V. Of musculary motion, VI. Of the anatomy of the brain, VII. Of the description and uses of the nerves, VIII. Of convulsive diseases : the first part, though last published, with large alphabetical tables for the whole, and an index ... : with eighteen copper plates / Englished by S.P. esq.

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

IT is not our intent, nor will it be needful for us to delineate the figures and situa∣tion 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 Entries is superfluous. Besides also, by what means the Nerves, arising within the Skull with their ramifi∣cation or branching forth, enter the dens and caverns of the Bones, shall be delivered particularly 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 without 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 controverted among Physicians concerning their frame and use. But we will first speak of the pituitary Glandula, because this part, being placed higher, is observa∣ble 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

[illustration] brain of a foolish youth

Fig. IIII

more strictly, sometimes more loosly: For in a Dog, Cat, and some other Creatures, stick∣ing to the Tunnel, it is pulled away together 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 Meninx 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 and 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 a 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 ei∣ther greater or lesser. For truly in some Animals the Carotidick Arteries being di∣lated within the Skull, are presently divaricated into Net-like infoldings, and from those infoldings many shoots of the Vessels every where enter this Glandula, 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 distributions of the Vessels, with the various proportion of its bulk. Be∣cause it is observed in some Animals, as chiefly in a Man and a Horse, that this wonder∣ful 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 fewre branches enter 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 san∣guiferous Vessels enter this Glandula: for if an inky liquor be squirted into the Caroti∣des 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 colour. Wherefore without doubt, it may be thought, that this Glandula doth receive into it self the humors, 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 Ex∣periment 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 Ca∣rotidick Artery lyes 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, some∣times 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 border 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 Ves∣sel 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 manner ∽ ∽.

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, before 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 sin∣gle 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 di∣stinct 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 complicated 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 existing; 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, pailes straight into the Brain.

The aforesaid Infolding is, commonly called the wonderful Net, and that deser∣vedly, for there is nothing in the whole fabrick of the animal Body more worthy of admiration; in which, besides the arterious little branches which proceed from either of the ascending Carotides, the veinous shoots, though fewer, meet with those de∣scending 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 di∣varications 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 Ker∣nel; 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 Artery.

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 inject∣ed 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 Prae∣cordia, even to the lower Region of the Body; when in the mean time, little or no∣thing 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 footsteps 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 covering the Brain: wherefore rather than the force should be carried to the Brain by the violent impulse of the liquor, it, return∣ing 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 provident (and to be equalled by no mechanical Art)

[illustration] interior base of a human skull

Figura V.

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 ingrafted; 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 over∣whelmed 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 rushing with too full a tor∣rent, should drown the chanels and little Ponds of the brain, the flood is chastised or hindred by an opposite Emissary, 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 wonderful artifice. For when the anterior bosoms transfer their load into the two Laterals, which are the posterior, and they them∣selves 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 whenas 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 covered 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 with∣out 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 Argu∣ment 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. The 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.

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.