A systeme of anatomy, treating of the body of man, beasts, birds, fish, insects, and plants illustrated with many schemes, consisting of variety of elegant figures, drawn from the life, and engraven in seventy four folio copper-plates. And after every part of man's body hath been anatomically described, its diseases, cases, and cures are concisely exhibited. The first volume containing the parts of the lowest apartiments of the body of man and other animals, etc. / by Samuel Collins ...

CHAP. XXXV. Of the Fabrick and substance of the Brain.

THe Brain, the most noble part of the whole Body, in reference to its Divine operations, hath a Fabrick fitted to accomplish them, being finely composed of great variety of minute Fibres, seated one above another in excellent order.

And that we may make a better inspection into these curious minute Bo∣dies, it may not be (as I conceive) unworthy our notice to treat of these particulars; The Origen, Nature, Figure, Progress, Uses, and Actions of these Fibres.

As to the first, * 1.1 they may be considered in relation to their generation or dispensation; as to the later, they borrow their Roots from the Cortex, and if taken in order of Generation, they derive their birth from the more viscid part of the Seminal Matter, which being first colliquated by the heat of the Uterus, into a thin Cristalline Liquor, is afterward somewhat indurated, and as it were coagulated by a quantity of Volatil Salt into a white clammy sub∣stance, divided for the most part into most numerous Fibres, which leadeth me to the nature and substance of them, * 1.2 as they are most solid and tough Particles of the Brain, whose greatest part is a curious Compage made up of innumerable nervous Filaments, and Vessels, whose empty Spaces are inter∣lined with a soft kind of Parenchyma, which is nothing else (as I conceive) but the Animal Liquor affixed to the outside of the Vessels.

These minute Fibres are most evident in the Brain of some Fish, which is composed in a Holybut, of an innumerable company of small long Proces∣ses, and are, as I conceive, upon a strict survey, nothing else but so many minute Filaments, so curiously joyned together with little thin Membranes, that they seem to be one entire Body, running all along from the anterior to the posterior region of the Brain, consisting of many subordinate ranks, seated in great order one under another; So that I conceive these numerous Filaments to be a system of Vessels containing and transmitting Animal Li∣quor through all the Coasts of the Brain, which I more plainly perceived in the Brains of Fish, which being wounded, and the Filaments cut, imme∣diately out of them quickly destilled a quantity of serous Matter, which is without question nervous Juice, flowing out of the wounded Filaments of the Brain, which being held over the Fire, did coagulate into a white sub∣stance, not unlike the White of an Egg.

So that the Compage of the Brain of different Animals, * 1.3 Men, Beasts, Fowls, and Fish, are framed of a number of Globules, as so many small Bodies of various shapes and sizes.

These Globules (as I apprehend) are aggregate Bodies, consisting chief∣ly of Fibres, and some Arteries and Veins, and perhaps Lymphaeducts, which may be worthy a curious search, because it is not altogether unrea∣sonable to imagine, where so many various, nervous Fibres are lodged, that they may be accompanied with Lymphaeducts as well in the Brain, as in other parts of the Body.

As to their Fabrick, * 1.4 these Globules being a great company of greater and less Tubes, and Fibres, formed (as I conceive) in larger or smaller Arches, one seated above another, the greater being placed near the ambient parts, grow less and less, as they approach the inward Recesses, till at last they come to a kind of plain, into the middle of these Collective Bodies, which in their Figure and Colour very much resemble Glands, and so may truly deserve this appellative, in relation as they are consigned to the same use with Glands to percolate the Liquors of the Brain, and render them fit for the Generation of Animal Juice, which may be produced, (as I fancy) after this manner.

The Albuminous part (being in confederacy with the Juice) when it is transmitted into the body of these Globular Glands, the purer part be∣ing secerned and impregnated with Volatil Salt, is received into the Origen of the nervous Filaments, and so by degrees conveyed through all the Proces∣ses of the Brain.

As to the Figure of these small Fibres, * 1.5 the white streaky Particles of the Humane Brain are divided into a multitude of little depressed round Processes, somewhat resembling those very minute Intestines, those small Bodies, that make the bulk of the Testicles, and are so remarkable in the Ventricles and in the Brain of Fish, that if they be exposed to the opposite light, they may be discovered to be ranked in such order, that they running in parallel Lines, represent the Teeth of an Ivory Comb, and in the Cerebellum, many Lami∣nae are seated upon each other, from which many nervous Filaments sprout∣ing out and equally spreading toward the Surface, do represent the Branches of Trees, variously sporting their smaller Twigs clothed with tender foliage.

These minute Fibres being the Prima Nervorum Stamina, the very Line∣aments in which the Nerves are first designed.

And do borrow their birth from the ambient part of the Brain, implan∣ting their tender winding Fibrils into the Cortex, which are thence propa∣gated through the Corpus Callosum, transversly overspreading, as with a Seeling the arched Chambers of the Brain, and afterward the Medulla oblon∣gata is all beset with nervous Filaments, very conspicuous in the Corpora striata, the first beginnings of the Medulla oblongata, and may be called Duo Vasorum Fasciculi, two rare systems of Filaments, passing through the Cau∣dex of the Medulla oblongata, and at last uniting themselves toward the lower Region of the Medulla, do constitute the bodies of Nerves, made up of these numerous Filaments; And now I will not insist any longer upon the rise and progress of these Fibres, because I shall have occasion to discourse more fully of them hereafter.

As to the uses of these numerous Filaments, * 1.6 the first may be to fortifie the Brain, whose Parenchyma being of a tender fluid nature, would easily be removed out of its proper place, were it not supported by these more solid Fibrils, which are the more firm Particles of the Brain, and are as so many Fulcra to under-prop it, lest in violent concussions, this soft Fabrick being very ponderous, should subside and compress the Capillary Vessels, inter∣cepting the due motion of the Blood.

Another use of the Nervous Filaments, may be as Repositories, * 1.7 or rather minute Chanels of the Animal Liquor wherein it is conveyed through the various Processes of the Brain, into the body of the Nerves, which is much quickned by the accidental motion of the Brain, caused by the pulsations of Arteries, but principally by the gentle, natural, opposite motions, produced by contraction and relaxation of the Fibrils, flowing from the dictates of the

Appetite and sensitive operations, more intensely or remissly framed accor∣ding to the more passionate or cooler inward acts, or according to the brisker or fainter impressions, made upon the Fibres of the sensitive Organs by stronger or weaker appulses of outward Objects; But I refer the more large discourse of the uses and actions of the Fibres, and that of the Nervous Liquor trans∣mitted between their various Filaments, to a farther discourse.

The whole Compage of the Brain emulating a Globe, is divided a great way into two equal parts, having a Fissure parting the Brain in the middle from the Surface to the Corpus Callosum, in which is lodged a Duplicature of the Dura Menynx, * 1.8 dividing the Orb of the Brain into two Hemisphaeres † 1.9, so styled by Learned Dr. Willis, which rather (as I humbly conceive) form two parts of one Hemisphaere, because if both sides were closely united, they would make but half the Globe, unless the partition were made from the furface to the base of the Brain, which is only made in the hinder part lying on the Cerebellum: And therefore the two upper sides distinguished by the Falciforme Process being separated from the Corpus Callosum, may be more properly called two portions of one, then two distinct Hemisphaeres.

As to their situation, * 1.10 their upper Region confineth upon the Pia Mater, and their lower on the Corpus Callosum; Their middle on the Falciform Process; Their Surface is beautified with a pleasant prospect of various Circumvolu∣tions full of numerous Branches, and Capillary Arteries and Veins, ascending and descending into them, and above all, adorned with a multiplicity of mi∣nute nervous Fibrils, the first rudiments of Nerves.

These Anfractus consist of a Cortical, Cineritious, and a more bright Medullary substance, which are so finely interwoven with divers insertions made one into another, that they will admit no separation, but the more inward Recesses of these Hemisphaeres are more entire, being framed of a white Medullary substance derived to the Corpus Callosum.

Notes

• * 1.1

  The Origen of the Fibres.
• * 1.2

  The Compage of the Brain is made of minute Fi∣brils.
• * 1.3

  The substance of the Brain is made up of many Glo∣bules in Ani∣mals.
• * 1.4

  The Globules of the Brain are a compa∣ny of Vessels.
• * 1.5

  The Figure of the Fibres of the Brain.
• * 1.6

  The first use of the Fila∣ments of the Brain.
• * 1.7

  The second use of the Fi∣laments of the Brain.
• * 1.8

  The Hemis∣phaeres of the Brain.
• † 1.9

  T. 46. F. 1. a a a a.
• * 1.10

  The situation of the Hemi∣sphaeres.