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. LIII. Of the Optick Nerves of Man, and other Animals.

THE Second pair of Nerves called the Optick † 1.1 is very large, * 1.2 and of a soft Compage, composed of many Filaments, enwrapping in their inmost Recesses a Medullary substance.

Diemerbroeck assigneth their Origen to the Corpora striata, seated in the Third Ventricle. This Author saith, that the outward Coat of these Optick Nerves is expanded about the streaky protuberancies, and is so blended with their substance, that their Fibres are united to each other; but I humbly con∣ceive it more agreeable to Autopsy, * 1.3 to derive the rise of the Optick Nerves from the Medulla ablongata, which thence pass obliquely forward, and in∣ward, near the Corpora striata. The Right Nerve, according to Vesalius, is carried toward the Left Eye, and the Left Nerve toward the Right Eye, * 1.4 and a little descending with a circumference, do meet about the Infundibulum, where they are united, not only by a decussation, but by an intimate em∣bodying each others substance, as Mercatus, Sennertus, Bauhinus, and other Learned Anatomists will have it: But it may seem more probable and con∣sonant to Sense, that the Optick Nerves are only conjoyned by Membranes in a simple Contact, and not by any confusion of substance, as it is confirm∣ed by the observations of many Learned Anatomists. Vesalius, Aquapendens, and Valverda have observed the Optick Nerves to be parted in their whole course, from the Brain to the Eye, In adolescente nervos visorios congressu in∣vicem non connasci, ne{que} sese contingere vidimus, saith Vesalius, Et ipsum de visu nunquam conquestum fuisse visu praestanti semper valuisse & familiares de viso∣rum duplicatione nihil unquam intellexisse.

The Optick Nerves after they are united, part again, and on each side, are transmitted through holes of the Os Sphaenoeides, and inserted somewhat laterally into the Coats, near the center of the Eyes in Men, at last deter∣mining into an expanded soft Membrane, upon which visible objects make their appulses, immediately producing Sight.

In a Fish called a Base, the Optick Nerves intersect each other, * 1.5 and do not at all mingle with each others Substance and Filaments, but only the out∣ward Coats do closely conjoyn near the Bone seated in the middle of the Brain, which on each side encloseth the greatest part of it; and the Optick Nerves also in a Gurnet do decussate each other, the Left Nerve passing to the Right Eye, and the Right Nerve to the Left Eye.

Eustachius found out the Optick Nerves all made up in folds, after the manner of sine Linnen Cloth. In optico ait ille se comperuisse, scilicet eum compli∣catum esse, veluti tenuissimum matronarum linteum in rugas innumeras aequales, pari serie distributas, & tunicula eas ambiente coactuni, qua incisa evolvi, & in amplam Membranam totam explicari posse.

The Optick Nerves in a Bustard do spring out of Two oval Processes, * 1.6 con∣joyned to the Base of the Medulla oblongata, and do closely unite themselves without any decussation; and then after a little space are divided, and pas∣sing obliquely, do insert into the inside of the Eyes.

The Optick Nerves also in a Goose do arise after the same manner, * 1.7 out of the Oval Protuberancies, appendant to the Medulla oblongata, and are conjoyned in a Node only, without any intersection, and then part taketh on each side an oblique progress to the Eyes.

In a Teal also the Optick Nerves are derived from the Oval Prominencies affixed to the Medulla oblongata, * 1.8 and bing parted at first, do after a small space unite without any Decussation (as is frequently found in Fish) and are only conjoyned to each other so firmly, that they cannot be divided with∣out laceration, and as soon as they are united, they presently after send out two large Trunks, which running transversly, are inserted into the inward region of the Eyes.

And having opened diverse other Brains of Birds, I have found the Optick Nerves to have the same Origen and Conjunction without any intersection, with those above described Fowl.

The Optick Nerves in a Turbut take their Origen from the Medulla oblon∣gata, * 1.9 under the middle Processes, and do decussate each other, and then pass an Inch and half, and arrive the Eyes: The Nerve of the Left side ma∣king its progress to the Right, and the Nerve of the Right, into the Left Eye.

In a Skate the Optick † 1.10 and Motory Nerves accompany each other, of which the Opticks are the largest, * 1.11 and First in order, being derived from each side of the Medulla oblongata, not far from the Medulla Spinalis, and do creep under the lateral Processes, to the sides of the Skull, which they per∣forate about an Inch from the lateral Processes.

The Optick Nerves in a Pike, * 1.12 take their rise from the middle Processes, and do like a Turbet intersect each other, that of the Right passing to the Left, and the Left to the Right Eye.

After the same manner the Optick Nerves in a Gurnet decussate each other; * 1.13 and do arise out of the Medulla oblongata, under the Anterior Process of the Brain.

The Optick Nerves of a Mullet do issue out of the Base of the Medulla ob∣longata, * 1.14 and not far from the Apex of it, and do plainly intersect each other.

After the same manner the Optick Nerves of a Soal do cross each other, * 1.15 and do derive themselves from the Medulla oblongata, under the lower Regi∣on of the middle Processes, and are joyned together for some little space, and then part, intersecting each other.

The Optick Nerves of a Cod do spring out of the Medulla oblongata, * 1.16 near its Origen, and do unite themselves without decussation, and then pass un∣der the Olfactory Nerves, making their address to the Eyes.

Notes

• † 1.1

  48. P P.
• * 1.2

  The Optick Nerves.
• * 1.3

  The rise of the Optick Nerves.
• * 1.4

  The Optick Nerves are not mutual∣ly embodied, as some phan∣cy.
• * 1.5

  In a Base the Optick Nerves inter∣sect each other.
• * 1.6

  The Optick Nerves of a Bustard.
• * 1.7

  The optick Nerves of a Goose, and their rise.
• * 1.8

  The rise of the Optick Nerves of a Teal.
• * 1.9

  The Optick Nerve of a Turbut.
• † 1.10

  T. 61. F. 1. k. k.
• * 1.11

  The Optick Nerves of a Skat••e
• * 1.12

  The Optick Nerves of a Pike.
• * 1.13

  The Optick Nerves of a Gurnet.
• * 1.14

  The Optick Nerves of a Mullet.
• * 1.15

  The Optick Nerves of a Soal.
• * 1.16

  The Optick Nerves of a Cod.