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

BElow the Chambers of the Optick Nerves in a common Valley which lyes be∣tween the tops of these and the Buttock-form Prominences, is placed the Pi∣neal 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 endued 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 Fa∣culties to 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, al∣ways placed nigh the holes or passages, open to the Tunnel, the Choroeidal Infolding is continually joyned; yea this infolding (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 Marrow, 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 in∣folding is beset with very many lesser Glandula's or Kernels, and every where inter∣woven with them, which imbibe the Serum secreted 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 Glan∣dula sustains and keeps duly stretched out the Chroeidal 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 Choroeidal infolding: Concerning which there will be little need to refel that Opinion of the common 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 Ventri∣cles of the Brain, or the Cavity 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 infolding 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 remaining portion of the bloody Latex might become more pure and free from dregs to be distilled forth into 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 remand∣ed back towards the Heart. In the mean time, lest the Serum, too much redound∣ing,

and boiling up in these Vessels, might hinder circulation, its superfluities are received 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 callous 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 Spirits, 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 con∣tained 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 figured; to wit, that another sort of commodity might result from thence; that when the Vessels of that Infolding, carrying too watry blood, lay aside more Serum than the Glandula's are able to receive or contain, what is superfluous might slide down opportunely into the underlying Cavity, as into a Sink. Wherefore the Pineal 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 Prominences, which are commonly called Nates and Testes. These being placed near together, do constitute as it were four Mole-hills, which yet are joyned one to another by certain processes. Beneath these Mole-hills, or rather be∣tween the joyning of them and the trunk 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-extremity of it opens before the former Mole-hills 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 Protuberances are far greater in some brute Animals than in a Man, as in a Sheep, Calf, Goat, and the like; also in a sound, 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 Testes, Buttocks and Testicles.

Notwithstanding, to what office these parts were designed, neither have the ancient Anatomists delivered, nor will it, by the help of Reason, be easie to guess for cer∣tain. 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 Fun∣ction, to wit, by affirming that these double shanks, on either side, were so many distinct ways of passage through which the animal Spirits, for the performing of mo∣tions, flowed from the Brain and Cerebel into the oblong Marrow, 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 Mar∣row 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 me∣dullar 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 certain communication; yet it seems that there lyes open a passage from those little lumps into the Cerebel, and not from this, through them into the oblong Marrow. For out of these aforesaid Prominences a medullar Process ascends obliquely on either side into the Cerebel, by whose passage the animal Spirits, tending from 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 influences, 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 Pro∣tuberances serve, we shall make this conjecture. The animal Spirits perpetually flow out and leap back again from the fountain 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 impulse 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 passage of the oblong marrow; and these Promi∣nences 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 en∣trances of their passage, from whence they go forward by the passage of the medullar 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 com∣mon Sensory from a double Organ of any Faculty) ought to be confounded and min∣gled 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 another; which connexion indeed of them, because it ought to be distinguished every where from the medullar Trunk lying under it hence, from the separation or empty space that comes between the oblong marrow and the grow∣ing 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 common 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 Prae∣cordia and Viscera, might be communicated to the brain. These reciprocal com∣merces 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 exerci∣ses of these involuntary Faculties should very much disturb 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 from Anger, Sadness, Pleasure, and other Affections, the Praecordia are disturbed, whe∣ther 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 va∣rious 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 original 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 answera∣ble to the same passion.

But the aforesaid Prominences and their dependences serve no less also for the con∣veying of the impressions of natural Instincts to the Brain, that from thence the Ap∣petite and local motions might presently 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 Protuberances; 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 Passions and Instincts to be made apart in this by-place; for why are not the commerces of the animal Spirits 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 reciprocal mo∣tion 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 between 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 Hypo∣thesis 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 Cerebel, 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 Excrescences of the former, will clearly appear to any one beholding them. But this, as we have already hinted, 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 pro∣cess 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 Nerves 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 Trochlear 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 receive and communicate to the Brain the natural Instinct delivered from the Heart and Bowels to the Cerebel; 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 Affections 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 conce∣ptions 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 Prae∣cordia, 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 sliding 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 distem∣pers and meltings, and not seldom deadly, of the vital Spirits, as I have observed in the bodies of many dying of Cephalick Diseases.