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. V. Of the Eyes.

THE Eyes are seated in the highest story relating to the beautiful Fa∣brick of Man's Body, for the more advantageous sight of distant Objects, and are placed above the middle apartiment near the confines of the Brain, as Guards to secure it from the dangerous encounters of ill accidents, and to conduct our steps in their prosecution of those due methods, instituted by Nature for the preservation and accomplishment of our meaner and more excellent parts and functions both of Soul and Body.

The whole Compage of the Eye is a system of many parts of different nature of Muscles, * 1.1 Membranes, and Humours, which do depend upon each other, and are all subservient to the noble as well as pleasant and useful fun∣ction of Sight.

The Eyes may be styled Appendages of the Brain, as being affixed to the Medulla oblongata, by the interposition of Optick Nerves, which give them Sense and Motion, as assisted with Muscles.

The greatest part of the Eyes are lodged in fit Cavities, * 1.2 (resembling the segments of a Sphaere) and well fortified both behind and laterally with strong Concave Bones (in which these finer Orbs sport themselves in variety of motions) perforated with many small Pores in the upper region of their Cavities through which destilleth a thin liquor from the Brain, bedewing the Eyes, (rendring them more pliable) to refresh them, lest they should be hot and parched by constant motion.

The tender and lateral regions of the Eyes are safely immured in Cavities, surrounded with the Bones of the Forehead and upper Mandible, with the upper and lower fine Integuments, with which the anterior part of the Orb of the Eye is vailed and unvailed at our pleasure.

These upper and lower Lids are composed of a tender Skin, * 1.3 under which is seated the Membrana Carnosa, attended with a very thin Pericranium. The variety of parts rarely enfolded one within another, hath its extremity en∣circled with a Limbus, fringed with fine Hairs, like so many Rays emitted from a thin Cartilaginous Margent.

The lower Eye-lid taketh its rise from the margent of the upper part of the superior Mandible, * 1.4 and terminateth near the close of the anterior part of the Eye; This is conceived to be immovable.

But the upper proceedeth from the Supercilium, * 1.5 and is terminated near the upper region of the Eye-lid, and endued with contrary motions of open∣ing and shutting, performed by the contractions of different Muscles.

The Elevator of the upper Eye-lid † 1.6 hath its origen about the Foramen of the Optick Nerve within the Chamber of the Eye, * 1.7 and being deduced from a thin carnous principle, is expanded into the margent of the upper Eye-lids ending in a broad thin Tendon: This Muscle being contracted, lifteth up the Eye-lid by drawing it into diverse wrinkles, by which the Eye is laid open and bare.

The Antagonist Muscle of the upper Eye-lid, * 1.8 according to Learned Vesa∣lius, Westlingius, and Bartholine, is a single Orbicular Muscle, seated be∣tween the Membrana Carnosa and Pericraneum, near the roots of the Nose, and taketh its origination from the inner Angle, and is carried under the lower Lid with Orbicular Fibres to the outward Angle, and afterward en∣circleth the upper Lid, and maketh its insertion into the greater angle of the Eye, * 1.9 where it began. This Muscle at the first sight seemeth to be an Or∣bicular Muscle, but upon a strict enquiry it may be discovered to be two Semicircular Muscles; of which the upper and greater, seated in the upper Lid, borroweth its beginning from the inner angle of the Eye, near the Nose, and passing from thence, the whole length of the upper Lid is inserted into the outward angle of the Eye, taking up the whole space between the Eye∣brow and the Limbus of the upper Lid, and being moved downward, smootheth the upper Lid, and covereth a great part of the anterior region of the Eye.

The other Semicircular Muscle ariseth with an acute origen from the side of the Nose a little below the other, * 1.10 and passing cross the lower Lid, and ri∣sing a little above the lesser angle of the Eye, is implanted with a broad in∣sertion into the upper Lid, to which it exactly closeth the under Lid, by rai∣sing

it somewhat upward. * 1.11 So that these minute Semicircular Muscles have contrary motions, the Muscle of the upper Lid pulleth it down, and that of the lower a little lifteth it up, wherefore it is evident they are divers Muscles, as having distinct Originations and Insertions: And Learned Diemerbroeck hath well observed, Quod in faciei Spasmo Cynico, saepe inferiorem palpebram immobilem & veluti convulsam, & deorsum detractam subsistere, dum interea superior naturaliter movetur, quod fieri non posset si utra{que} palpebra ab uno Mus∣culo moveretur.

The Semicircular Muscles perfectly closing the Limbus of the Eye-lids by different motions, do draw the Curtains of the Palpebrae, and give the Eyes a repose and retirement in the silent Night, from the frequent sollicitations of troublesome Visitants, the various resemblances of visible Objects, upon which the Eyes, when we are awake, do perform a duty of attendance to give intelligence to the Brain, their Supreme Lord and Maker.

About the confines of the Eyes and forward, we meet with the Supercilia, * 1.12 being two prominent small Arches seated in the upper margents of the bones of the Eyes, and covered with a thick Skin, curiously shaded with semicir∣cles of Hair, not so much ornamental to the Face, as serviceable to the Eyes, to receive Dust and Humors descending from the Forehead, which would else surprise the Eyes, and by rendring them uneasie, would hinder their sight and motion.

About the greater and inward Angles of the Eyes, are placed the puncta Lacrymalia, small Cavities more conspicuous in great Animals, and in per∣sons given to weeping; through these small perforations flow little Rivulets in so great a quantity, upon the surface of the Eyes, that they overflow the banks of the upper and lower Lids, besprinkling the Cheeks with great drops, the sad heralds of the Mind, disguising the Countenance, and proclaiming the passionate sorrow of some importunate loss.

Most Ingenious Steno hath discovered many short Ducts arising about the roots of the Cilia, which hardly can be seen, unless the Membranes (when the bones of the Nose are broken) be left entire.

These Excretory Vessels creeping down on each side of the Nose do dis∣charge a serous liquor into its Cavity, in Sheep, Calves, Hares and Coneys; * 1.13 They do not arise exactly at the roots of the Cilia, but more inward, and are yet more deeply seated in Birds, in which they are larger than in other Animals, and terminate into the chink of the Palate; In Horses the Vessels are transmitted from the Eye, and are continued in the whole length of the Nostrils, and terminate into the Extremity of the Lachrymal Vessels in the Eye-browes of Men.

These Excretory Ducts may be comprised under two kinds, * 1.14 the one con∣fineth on the outward angle of the Eyes, and do relate to the Glands seated in it. And the other kind of Lachrymal Vessels do discover themselves about the extremity of the Limbus belonging to the Eye-lids, and do tend toward, and at last creep under the Glands lodged about the greater angle of the Eye.

And also Aquapendent, and Marchetti, have found out two Perforations about the lesser angle, observing the same order with those of the greater.

But beside these Excretory Vessels, Meibomius, after a most curious search, hath discovered Fifteen more in each Eye-lid, flowing from so many minute Glands lodged in them, and terminating all round the margent of the Lim∣bus, encompassing the upper and lower Eye-lids.

In the angles of each Eye easily may be discerned two Glands, * 1.15 the less is seated in the inward angle of the Eye, styled commonly Caruncula Lacry∣malis, which is a thin small Gland, made up of a lax spongy substance, and some part of it is lodged in a Cavity of the first Bone of the upper Mandible,

through which a Perforation is made from the Eye into the Cavity of the No∣strils. This Gland seemeth partly to be instituted for a Cover of the Cavity, passing between the Eye and Nostrils. But in the Eyes of Calves, Sheep, and Horses, this Gland is not so situated at the angle of the Eye, as to be out∣wardly discovered, but in its stead a Lump ariseth outwardly Membranous, and inwardly Cartilaginous, to which is appendant an oblong Gland; upon the middle of it taken longways, adjoyneth a long broad Cartilage, which I conceive, in some manner conduceth to the expansion of a Membrane, which cleanseth the Eyes of many Animals, thereby quickning the sight.

Rolfinchius hath discovered Vents passing out of the Glandula Lacry∣malis into the Nostrils, * 1.16 which the Learned Author saith are so large in Calves, that from thence may be transmitted a Brisle into the Cavity of the Nose.

The other Gland of the Eyes (which is called the Superior, and Ante∣rior, and sometimes the Greater) is lodged in the smaller and outward angle of the Eye, a little above the first common Suture of the upper Jaw, about a rough chink, where it helpeth partly to fill up the orbite of the Eye.

This Gland is three times as big as that of the inward Angle, not perfectly round, but somewhat broad, and blackish, and is endued with an imperfect Circular Figure, as being unequal in its Perimeter.

This Gland in a Calf filleth up a great part of the upper region of the Eye, whose Lymbus is divided into divers Lobes, accompanied with many Excretory Ducts, running between the Interstices of the indentments.

This Gland (as well as that of the greater Angle, * 1.17 and those of the Eye-lids) is accommodated with many Arteries, derived from the Caro∣tides, and Veins from the Jugulars, and Nerves from the second, third, fourth, and eighth pair of Nerves.

Thus having given a brief description of the Glands relating to the Eyes and Lids; it may not be amiss to speak somewhat of their uses.

The first and most common is to be Colatories of the most select Liquors of the whole Body, of which the first being Vital, is transmitted by the ter∣minations of Carotide Capillary Arteries, into the substance of the Glands, appertaining to the Eyes and Lids, and the Blood being refined, is after∣ward returned by the Jugular Veins; and the other Liquor is imparted by the extremities of Nervous Fibrils inserted into the body of the said Glands, in which the Nervous Liquor being depurated, the purer part is carried by Pores into the substance of the numerous Vessels, while the recrement of the Nervous Liquor is carried into the origens of the Lymphaeducts, or fometimes through the Excretory Vessels, terminating near the Lymbus of the Eye-lids, bedewing the surface of the Eyes with a shower of Tears, which being exuberant, do overflow the confines of the Eyes, and drop down the Cheeks, or else are diverted through more secret Channels leading into the Nostrils.

Having spoken somewhat of the neighbouring and ministerial parts of the Eye, I will now come to its Integral parts.

The Figure of the Eye is round, * 1.18 as more fit for motion, and may be well called a Globe in a lesser model, springing from that greater of the Brain, to which it is allied by the entercourse of Arteries, Veins, and Nerves, which impart life, nourishment, sense and motion to the Eye, which may be after a manner compared to a Bulbous Root, united to the Earth by Fibres, as the Eye is conjoyned to the Brain by Nervous Fibres and Vessels. And the best instance among Bulbous Roots to represent the Eye, is that of the Onion, consisting of divers thin Coats enwrapped one within another, wherein in some sort are resembled the various Membranes of the Eyes.

I will begin with the Ambient parts, the Muscles and Membranes as the Circumference of this fine Globe, and then of the Humors, contained in the

more inward recesses of the Eyes: And here observing Natures Method, * 1.19 I will treat first of the Muscles, which are Six in number in Men, and Se∣ven in Beasts: Four of them are named Recti, quoniam rectis inserviunt motibus, and equal as well in thickness, as greatness, and derive their begin∣ning from the inward region of the bony allodgment of the Eye, near the holes, which give admission to the Optick Nerves, and being carried under the Tunica Adnata, do terminate into thin Tendons near the verge of the Cornea.

The first of the Muscles being contracted, lifteth up the Eye, † 1.20 and is cal∣led Superbus, by which we speak our pride in Supercilious looks. * 1.21

The second is opposite to the Musculus superbus both in place and office, as depressing the Eye, and is named Humilis † 1.22, because the Humble have an aspect downward, attended with a modest bashfulness and respect.

The third, Musculus Adductor, † 1.23 which draweth the Eye toward the inward angle, and is stiled Musculus bibitorius, the drinking Muscle, wherein the sober person maketh his measures of drinking to gratifie his necessitous appe∣tite, whereas a Good Fellow with this Muscle indulgeth his Eye in the plea∣sant froliques of more free Cups.

The fourth right Muscle of the Eye (called Abductor) † 1.24 turneth the Eye outward to the lesser Angle, and is called Indignatorius, the angry Muscle, * 1.25 wherein we express our passion in a severe withdrawing our Eye to give check to any thing offending us.

Thus much of the Right Muscles, I come now to the Oblique, * 1.26 which are two, of these the less in magnitude, and lower in situation † 1.27, borroweth its origen from the lower margent of the bony repository of the Eye, climbing obliquely upward to the outward angle of the Eye-lid, and terminates with a short Tendon near the verge of the Iris, and in its contraction pulleth the Eye obliquely downward to its lesser Angle.

The other oblique Muscle of the Eye † 1.28, being the longer and upper, hath the same beginning with the third right Muscle, and entreth with a thin body into a Cartilaginous Pully, and thence ascendeth obliquely to the upper region of the Eye, and terminateth near the end of the Tendon of the oblique lower Muscle of the Eye, and being assisted with its Pully, turn∣eth the Eye obliquely toward the inner corner: These right oblique Muscles are truly termed Amatorii, the Courting Muscles, because with these Lovers Court their Mistresses with amorous Glances, the attractive Prologues to more pleasant Scenes.

And the great end to which these oblique Muscles are designed, is to en∣large the territories of the Sight, which else without these Machines of Mo∣tion would be confined to a narrow compass, as capable only to discern those Objects which directly face them. But the Eyes, with the concurrence of these Muscles display themselves upward and downward, inward and out∣ward to treat us in their different motions, far and near, with great variety of most pleasant prospects.

These Muscles are terminated into divers thin Tendons, which are uni∣ted into the determination of one expanded Membrane, called by Columbus innominata, because it doth not deserve the appellative of a Membrane, as being rather a Tendinous Body springing from the right and oblique Muscles of the Eyes; and this leadeth me to their Membranes, those thin Vails in∣folding each other, parting the Eyes as into so many fine transparent Walls, giving reception to the visible resemblances of outward Objects.

The first Membrane presented to our view, * 1.29 in the White of the Eye, is the Membrana Conjunctiva, or Adnata; Quoniam ejus adminicula vicinis Oculi partibus adnascuntur, and taketh its origen from the Peri••ranium expanded, enclosing the Optick Nerves, and the greater part of the Circle of the Eyes, and is terminated at the circumference of the Cornea, lest the Adnata being an opace Body should shade the Cornea, and darken the Sight.

The second Membrane of the Eye is called by the name of Dura and Cor∣nea † 1.30, * 1.31 the greater hinder part being opace, is the Sclerotica † 1.32, enwrapping the more considerable part of the Eye, and is terminated near the Uvea, and de∣riveth its origen from the Dura Menynx, and investeth the Optick Nerve; and being first implanted into the hinder region of the Eye, is afterward expanded, and groweth of a greater hardness and thickness, than the other Coat from whence it springeth: This Membrane overspreadeth the hinder and some part of the anterior region of the Eye, where it making the Black of the Eye, resembleth in substance, colour, and transparency somewhat of Horn, whence I conceive it borroweth its name of Cornea, and may be rasped into thin pellucide Particles or Shavings, Perinde ac si ex laminis aliquot, seu squam∣mis invicem compactis, constituentur.

The Cornea or Black of the Eye is not adorned with a perfect Sphaerical Fi∣gure, * 1.33 and is more protuberant than the 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉, and more enlarged forward, resembling the Segment of a Circle, or the lesser part of a Sphaere, not unlike the smaller portion of a little Ball, and is somewhat of a Hyperbolical, or rather of a Parabolical Figure; but in that part which is most Prominent, it doth imitate in some degree the roundness of an Orb: But if the Conforma∣tion be made both of the Sclerotica and Cornea conjoined, a right line drawn crosways may speak the Coalition of both parts of the Dura and Cornea, and the rise of the Processus ciliares, and of the Circular Term, and Diameter of the Iris; So that the Cornea is not beautified with an exact Orbicular, but Parabolical shape, in which the Radii Visorii, being more closely united, do make brisker appulses upon the Cornea for the production of a more clear Sight.

The surface of the Cornea is very smooth, * 1.34 and so free from all Asperities, as if it were polished by Art, for the better reception of the Visory Rays; and therefore in Antient Persons, where the moister part of the Cornea is ex∣haled, it groweth more dense and wrinkled: This disaffection is called by the Latines, Caligo, which is familiar to Aged people, and much labouring of the Jaundies; whereupon the Cornea is so affected with the thin Particles of Bile, that it tingeth the Visory Rays with Yellow, when they make Appulses upon the Cornea.

This Coat in its first rudiment is a fluid Body, * 1.35 which is derived from the more viscid parts of the Seminal Liquor, first producing a Membrane, and afterward groweth by several degrees more and more solid, by the accession of new Saline Matter, by which the Membrane at last is concreted into a kind of bony horny substance; and still upon the accession of more Saline Particles new Horny Accretions arise, producing divers Laminae or thin Flakes one seated above another, and so finely set together, that they seem to make one entire uniform substance, but indeed (as I humbly conceive) are composed of many thin Flakes, which may be brought off in shavings by divers Secti∣ons: These fine horny Accretions were once a thin fluid body, into which may be received many transmissions of Light, making passages every way through the pliable compage of an once liquid substance, whence it was so

ordered by the various displaying of Light, that such an arangement was made in the constituent parts of the formerly Liquid Body, that the same disposi∣tions continued, rendring it transparent, and capable of lucid transmissions, when it afterward acquired the more solid frame of the Cornea, originally a fluid body, and afterward turned into a horny substance by concreted, saline and earthy Particles; This Hypothesis may seem to be confirmed by many in∣stances of Salts (the Materia substrata of Glass) Jewels, and precious Stones; which being originally fluid, are afterward concreted into solid Transparent Bodies.

Salts of Vitriol, Alome, Nitre being reduced into small Particles in some proper Liquor, and then being left quiet, these scattered Saline Atomes will reunite, and grow concrete in the Liquors they are seated, by shooting them∣selves into Transparent Cristals adorned with fine, different, regular Figures, so that it must be always supposed, that these minute concrescent Parti∣cles may have a free play in the contiguous fluid Liquor, for the fit disposing of their parts; else the Saline Atoms in the time of their concretion, will be forced to conform their Figures to the inward surface of the Vessel, in which the Liquor is contained.

Salt of Nitre, if the Water (in which it was dissolved) be too much evaporated by boiling, and put into a Glass, the Nitrous Particles having not freedom to shoot in the Ambient Liquor into their proper determinate shapes, are unduly modelled into one rude mass according to the Cavity of the Glass; but the more remote parts from the surface of it having a greater liberty to shoot in the Liquor, are curiously formed into Transparent Con∣cretions, dressed with prismatick Figures, which are peculiar to Nitre.

And I also conceive, that the more solid substances of Precious Stones were originally Fluores in solutis principiis, and are afterward Coagulated by a lapidescent Juice into harder Transparent Bodies, endued with great variety of determinate shapes.

Learned Mr. Boyle, a Person of great Honor and Vertue, giveth a Nar∣rative of a famous Quarrey, seated near a Spring, which had somewhat of a petrescent disposition; This Honorable Author caused many solid rough Opace Stones to be broken, and thrown into the Spring of Water, hoping to find some Coagulated Juice in some finer substance, and accordingly found that in divers places, the solid and massy Stone had Cavities in it, with∣in which all about the sides, there grew Concretions, which being Transpa∣rent, and very curiously shaped, seemed to be some finer Lapidescent Juice, that by a kind of percolation through the substance of that grosser Stone, had at length arrived at those Cavities, and upon the evaporation of the superfluous aqueous parts, or by being soaked up by the neighbouring Stone, had opportunity to shoot into fine transparent Cristals, which were so great, as to overlay the sides of the Cavities.

Thus having shewed some analogy between the Cornea, * 1.36 and divers Salts and Precious Stones, how they were originally Fluid, and afterward Con∣creted into more solid Transparent Bodies, produced by a fine Lapidescent Juice coagulated, and curiously modelled into various regular Figures; Now I will endeavor to demonstrate the inward Texture of Glass and Precious Stones, as they consist of many thin Diaphanous Plates, resembling the fine flaky juxta-positions of the Cornea, between whose many Interstices the subtle beams of Light may freely infinuate, and every way display them∣selves.

It is generally conceived that Glass and Precious Stones have one uniform inward Compage; but upon a curious survey, they may be plainly disco∣vered to be systems made up of many thin Flakes, so neatly conjoyned, that they may well impose upon a naked Eye carelesely viewing their close Commissures: But if you hold up some very thin clear Glass against the Light, so that the Plate it self is scarce discernible by a negligent eye, and a more curious person cannot be brought to conceive that a thin plate of Glass may be divided into many Laminae, which though it be contrary to the vul∣gar opinion, yet it hath been experimented by following the Grain of the Glass that it may be split into many fine Plates.

And I conceive this Hypothesis may be farther proved, * 1.37 by diligent inspe∣ction of Precious Stones, decked with Geometrical Figures, seated in some parts of their furfaces, wherein with a quick Eye, may be discovered many parallel Commissures, shewing themselves in many contiguous edges of mi∣nute thin Plates, which seem to lie one over another, like the Leaves of a Book a little opened.

And also in Saphires and Hyacinths, it is possible to espy (by turning them divers ways to the Light) the fine conjunctions of the Flakes, and I conceive these Precious Stones will admit a splitting according to the Ducts of their Grain, which is commonly done by Artists in Diamonds, whose Laminae consist of parallel Plains; but if the Plains of the Plates run counter to each other, the Diamonds cannot be smoothly split, because the Com∣missures go unequally, making Angles in the body of the Stone; which I conceive, render the compage of the Diamond less Transparent and fowl (whereupon it is judged no Paragon) as intercepting the free displaying of the beams of Light within the cross Grains, and unequal run∣ning of the Commissures of the Plates.

Thus I have attempted to give an account of the nature of Glass, Cristal, and Gemms in their first production in Solutis principiis as Fluid Bodies, and in their greater maturity of more solid Compage (concre∣ted by fine saline and earthy Particles) made up of many thin Flakes, in which they hold a great analogy with the Cornea, and do illu∣strate the origen of its Transparency in a Fluid Substance, compound∣ed in a multitude of Atoms, interspersed with innumerable minute Spaces; whereupon the most small parts of Seminal Liquor, out of which the Cornea is originally formed, may be easily dissociated, and put upon motion from term to term, as it consisteth of so many active Atoms, interlarded with many minute Interstices, filled with thinner substances (every way receptive of Light) the first rudiment of Transparency in the Cornea, * 1.38 wherein the transmission of Rays pass every where through its porous Compage (when it is Fluid) so that the current made by pervious impressions are afterward retained, when the Cornea is coagulated into divers thin Flakes, as so many saline Accre∣tions, curiously conjoyned, whereupon the numerous rows of Parallel Plains and Surfaces (as every thin Flake hath an upper and lower Surface) are united in fine Commissures, into whose innumerable minute Pores, the subtle Aethereal Particles of Light may easily insinuate, and free∣ly display themselves, giving that pleasant transparency to the Cornea, as well as to Glass, Cristal, Gems, and other Diaphanous Bodies.

The next Tunicle of the Eye hath the Appellative of 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉 by the Greeks, and Uvea † 1.39 and Tunica uviformis by the Latines, as being like in colour to the Stone of a Grape; but I humbly conceive that it hath received this de∣nomination, rather from its orbicular Skin, as a Vesicle, encircling a trans∣parent Liquor, not much unlike that of the aqueous Humor of the Eye; By others this Membrane is called 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉, as resembling the Corion in the divarications of Arteries and Veins, finely enameling this Coat; which ta∣keth its rise from the Pia Mater, and encompasseth the whole circumference of the Eye, and its upper region is for the most part affixed to the Sclerotica, by the interposition of many small Arteries, Veins, and Ligaments, or ra∣ther thin Membranes.

Its inner Surface is supported by Swimming upon the aqueous Liquor, * 1.40 to which it is contiguous in its Concave Surface, and to the Sclerotica in its Convexe, and is of an orbicular Figure, as fitly complying with the round Figure of the ambient parts. Its inward Surface is beautified with one en∣tire uniform colour, being Black in Men, Yellow in Cats, and Sky-coloured in Bullocks.

The neighbouring Membrane is called Iris, ab Iridis Celestis similitudine, * 1.41 as it is painted in its anterior Region (where it is loose in reference to motion) with great variety of colours, sometimes Black and Hasle, and other times Blew, Green, Sky-coloured; so that its outside is airy and gay, but its in∣side hath a more sober dress of Sables, as hung with Black, rendring all the inward chambers of the Eye dark (rightly constituted by the All-wise Agent) that the visible resemblances being clothed with the bright Rays of Light, might not confound the Sense with their over-much splendor; and to that end the Beams of Light (investing the outward objects) receive a due allay with gloomy Shades in the dark recesses of the Eye, to attemper this great gayness, before they make Appulses upon the tender Organ of Sight.

This Membrane is a part of the Choroides, but according to Riolan it is a distinct Membrane, and may be separated, as the Author saith, from the Uvea, which he found in the boiled Eye of a Beast; but all other Anatomists are of a different judgment, holding the Iris to be one continued part with the Uvea, to which it is so firmly annexed, that they cannot be severed from each other, without offering a great violation to them: And the Iris, though it springeth out of the Choroides, as being one entire part with it, and is seated under the Cornea, yet it is not like to it, and Homocentrical with it, but is different from the Uvea, and all other Membranes of the Eye, which are whole, and entire Segments of their orbicular Surfaces; but the Iris be∣ing perforated in its Center, representeth a small Ring or Circle, through which the visible Images of things arrayed with beams of Light, are darted into the transparent humors of the Eye, and at last make Appulses upon the Rotina.

The Pupil of the Eye † 1.42 is a Perforation drilled through the middle of the Iris, and is oblong, or oval in Brutes, but orbicular in Mean, making a lit∣tle Circle about the Center of the greater Circle of the Iris, and is affected with various obscure motions, whereby it is gently dilated and contracted, according to the reception of the fainter, or brighter Rays of Light.

The Pupil is supported, as floating upon the watry Humor of the Eye, and is enlarged as it approacheth nearer to the Cornea, which is occasioned in sha∣dy places, and early in the Morning, and late in the Evening, wherein the Pupil is dilated to give a freer reception to the more obscure beams of Light;

And as the Pupil maketh its retreat inward, toward the aqueous Humor of the Eye, it is recollected by narrowing it self to deny admission to the too troublesome address of the brighter beams, into the chambers of the Eye.

And the Pupil is not only enlarged, * 1.43 to give a free access to fainter, and lessened to give a denial to over-bright Rays, but with them to give a re∣ception also to the visible resemblances of outward Objects, the one near, and the other remote; while we view the nearer, the Pupil is contracted; and when we see the more remote, it is dilated, which is occasioned (as I humbly conceive) by reason the nearer object is presented to the Cornea and Pupil in a greater Cone; whereupon the Pupil is contracted, that the Rays of the greater Cone might be the more collected, and formed in such a due proportion, by the Coarctation of the Pupil, and thence transmitted through the transparent, to the more opace part of the Eye, that the more obtuse Cone of the near object being reduced to a point, by the contraction of the Pupil, may make a more sensible Appulse upon the Retina: But the greater distance of the other Object rendreth the Cone more acute; whereupon the Pupil needeth no Contraction to lessen the Cone of the more distant Ob∣ject.

The Dilatation and Contraction of the Pupil, * 1.44 according to a regular course of Nature, are gentle and easy motions; and if they be celebrated with too great force and quickness, they offer a violence to the adjacent Membranes, which being of most acute Sense, are afflicted with pain in the over-hasty mo∣tion of the Pupil, as it is very evident, when we have conversed long in the dark, and are exposed of a suddain to a radiant Sun-shine, which being free∣ly and suddainly darted through the enlarged Pupil, it is immediately forced by a violent Contraction, to give a stop to the immoderate incursion to the importunate Sun-beams, whence ariseth a violent pain in the Eye.

The Pupil hath a different Magnitude, as the circumference is greater in some, and more narrow in others. They whose Pupil is naturally dilated see more confusedly, by reason the visible object is presented through a greater Perfo∣ration with an obtuse Cone, which maketh a faint Appulse upon the Organ of vision: But they on the other side have a more clear Sight, who are endu∣ed with a less Pupil, in which the Rays of Light (enwrapping the visible Image of things) passing through a small Foramen, are more collected and united, and presented in a point, and being transmitted through the Dia∣phanous parts of the Eye, at last make a more brisk Appulse upon the Retina.

And the Iris in several persons hath larger or more small Perforations, ma∣king greater or less Circles in the Pupil of the Eye, through which a more free or sparing proportion of Light is received into the transparent parts of the Eye, whence ariseth variety of Sight; They who are endued with a di∣lated Pupil, see best in the Night, and Shady places, and are offended in the Day with bright Rays of Light, which entring through a great Foramen of the Iris, give disturbance to the more tender parts of the Eye, confounding the Sight; And they who have a narrow Pupil, are less discomposed in the day, with the bright beams of Light, which being more sparingly enter∣tained through a narrow circle of the Pupil, give orderly and fair Appulses upon the Retina.

The Processus ciliares are so styled from resembling Hairs seated in the Limbus, † 1.45 or Margent of the Eye-brows. These rare Processes seem to repre∣sent so many Black lines, drawn by Natures fine Pensil, making as it were divers minute Shades in the transparent part of the Eye.

These Processes borrow their Origen from the inward Region of the Pe∣rimeter, relating to the Uvea, where it resteth upon the Crystalline Humor, * 1.46 and are many minute Filaments or Fibres passing into, and encircling the convex Surface of the Crystalline Humor, tying it to the inward Surface of the Uvea; and also these fine Processes do insinuate into the Retina, Aranea, and Hylaoides; and being every way twined round the Crystalline Humor, do form a kind of Ring, bespotted with Black, contiguous to the Uvea, in its convex circumference, and in its Concave to the Aranea, with which it is encompassed as with a Girdle, and then these curious Processes are like so ma∣ny Rays displayed into the Tunicle of the Retina, and Hylaoides, which by the interposition of these Fibrils, are so closely conjoyned, that they cannot be separated without the laceration of each other. * 1.47

So that (as I conceive) one use of the ciliary Processes, may be as so ma∣ny common Bonds of the Coats of the Eye, keeping them as well as the Humors, from starting out of their proper Sphaeres, in the quick rowling motions of the Eye. * 1.48

Another Use may be consigned to these Processes, to be as so many mus∣cular Fibrils, gently moving the Crystalline Humor upward and downward, inward and outward, toward the greater and less Canthus of the Eye; by reason Objects presented to it, some are near, and others more distant, some are placed before, and others at the side of the Eye; Whereupon the visory Rays displayed from these diversly seated Objects, concurring in several pla∣ces and points, need different refractions, that they be represented to the Retina in due order, as Learned Dr. Highmore hath well observed; Fibrae ita∣que hae Musculorum more se contrahendo & relaxando Humorem Cristallinum cui inseruntur, attollunt, aut deprimunt, donec radii ita refrangantur, ut illorum concursus sit in eadem paratela, in Retina, cum illis in oculum incidentibus. * 1.49

The Retina called by the Greeks 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉, ab amplect∣endo, a Latinis Reticularis, quod figuram retis aemuletur, as being somewhat like a Casting-net in Figure, as many famous Anatomists will have it; But I beg their pardon, and conceive it more probable that this Coat was called Reticularis from the numerous Veins and Arteries derived from the Uvea, and branched up and down this Membrane in a kind of Network, and not from the similitude of a Pooch, by reason upon that account, the Scleroti∣ca and Uvea may deserve the same name of Retiformis, as well as the Retina, in respect their Concave Surfaces do exceed their Haemispherical Surface, some∣what resembling a Casting-Net, as well as the Retina.

This Membrane taketh its rise from the pulpy substance of the optick Nerve, not altogether unlike that of the Brain, which is propagated all along the inward recess of the Brain, which being dilated, is the Origen of the Retina, which expandeth it self so far, as to encompass in its Sinus the vi∣treous Humor, and halfe the Globe of the Crystalline, where it is united to its thin proper Membrane, called 〈 in non-Latin alphabet 〉〈 in non-Latin alphabet 〉; so that the Retina arising from the optick Nerve, and almost encircling the vitreous Humor, is inserted into the terminations of the greater portion of the Sphaere belonging to the Crystal∣line Humor, giving a check to the exorbitant Flux of the vitreous Humor, and containing the Crystalline in its proper Sphaere. And the Retina being firmly conjoyned round about the Uvea, is a kind of Intersepiment, parting the Crystalline Humor and the Eye in the middle, and dividing them almost into two Hemispheres, though I confess the anterior is somewhat less then the Posterior.

Having discoursed of the containing part of the Eye, the Membranes, I will now speak of the Humors contained in them. The Aqueous Humor of the Eye † 1.50 resembleth Water in thinness, transparency, and fluidness; whereupon it having no proper Coat to determine its minute agile Particles (ever disposed to motion) is quieted and confined within the more solid terms of the neighbouring parts of the Iris, and Cornea above, and below by the Aranea, and Crystalline Humor.

According to Riolan, the Aqueous Humor floateth about the Vitreous, being also seated in the lower region of the Eye; but it is somewhat diffi∣cult to understand, how the watry Humor should be transmitted through the more solid parts of the Aranea and Crystalline Humor, to the Base of the Eye; wherein in a disaffected Eye, is sometimes found a Humor more thin and fluide then the Vitreous, but more Dense and Viscide then the Aqueous; exstilling from the Vitreous Humor through its broken Tunicle, and this Humor may be somewhat attenuated by the warm ambient Air.

The Aqueous Humor is excentrick to the Orb of the Eye, * 1.51 and hath no Figure of it self, but receiveth its configuration from the impressions of the more solid adjacent parts, the concave Surface of the Cornea and Uvea, make the anterior part of the Aqueous Humor convex, and somewhat orbicular, and the Convex Surface of the Crystalline doth render the inferior part of the Aqueous Humor Concave.

This watry Humor of the Eye is called by Avicen, An Excrement of the Crystalline Humor; Whereupon, when it is evacuated in wounds of the Membranes, relating to the Eye, and the wounded part being healed and closed up, the Aqueous Humor is restored again.

Galen giveth in his First Book De Symptom. Causis, and the Second Chapter, an instance of a Child, wounded with a Bodkin in the Pupil of his Eye, through which all the drops of the Aqueous Humor trickled down the Eye, like so many Tears; and the wound being cured, the Aqueous Humor was restored, and the Child recovered his Sight. Of the like disaffection Hilda∣nus giveth examples in his First Century, and Twenty First Observation.

I conceive the repair of the watry Humor, when evacuated in wounds of the Eye, doth not proceed from the Crystalline Humor, which being more solide, is nothing akin to it, and therefore cannot propagate this thin fluide Excrement (As Avicen would have it) through the Aranea: Again, if this Aqueous Humor be an Excrement of the Crystalline Humor, it must have some proper Ducts to discharge it, when redundant, which can no way be discovered in the Eye; I conceive it more probable to derive the repair of the Aqueous Humor from the Lympha of the Blood, distilling out of the ter∣minations of the Capillary Arteries inserted into the Uvea; and when this Aqueous Humor shall grow exuberant, it may be returned by the Capillary Veins.

The use of the Aqueous Humor of the Eye may be to support the Cornea and Uvea, * 1.52 and the Crystalline Humor, which being copious and well quali∣fied in young persons, rendreth the Cornea and Uvea so plump, that its Sur∣face seemeth too smooth and shining, as it were polished by Art; but in old Men the Aqueous Humor being somewhat exhausted, and ill disposed, the Cornea groweth flaccide and wrinkled.

This Humor in its natural Constitution, is thin and transparent to give a reception to the visory Rays, which are too much refracted in this Humor, when it is over Dense, whereupon the Sight is rendred dimme, by reason Objects are presented from thence to the Retina, as through a Cloud.

The Humor of the Eye, called by some Cristallinus † 1.53 and by others Glacialis, from the likeness it espouseth with Cristal or Ice, not in consist∣ence and hardness, but in transparence and colour, as Learned Vesalius will have it: But with the leave of this famous Author, I humbly conceive the Cristalline Humor to be only transparent, devoid of colour, having only an apparent, and no real Whiteness, which it borroweth from the bright beams of Light, sporting themselves in the inward Recesses of this transparent Bo∣dy, not hued with colour, with which if it were tinged, it would be ren∣dred uncapable to transmit various colours of visible objects (through its own Substance and vitreous Humor to the Retina) which though in them∣selves very different, would be represented under that one determinate co∣lour, with which the Cristalline Humor is predisposed, and it may be pro∣ved by reason, that every medium of Sight ought to be denuded of all colour, or else Intus Existens prohibet alienum.

And truly I cannot but wonder why this part of the Eye should have the appellative of a Humor (as it is commonly received by the Antient and Mo∣dern Anatomists) when it is not fluide, * 1.54 as being of a more solid Body then Liquors, somewhat resembling soft Wax in consistence; But I will sit down with the common denomination, rather then give a disturbance, Quoniam usus obtinuit.

This Humor hath halfe of its Orbe enwrapped with a thin Membrane, * 1.55 called Aranea, or Cristallina, which is extended from the upper Region to the middle, where it is united to the Retina.

The Figure of the Cristalline Humor varieth in several Persons and Ages, * 1.56 and the orbicular protuberance is not always uniform, and is different in the same person, occasioned by accidents and age, whose defects are supplied by Art in the invention of Spectacles, which are diversly contrived with more or lefs prominency, according to greater or less weakness of the Sight; and sometimes they are made Concave, (which is rare) when the Cristal∣line Humor is too protuberant, but most persons of ill Sight are gratified with Spectacles of a convexe Figure, by reason the Cristalline Humor being naturally endued with a Prominent parabolical Figure, is often deformed in old Age, with a broad depressed shape, because the substance of the Hu∣mor being somewhat abfumed, groweth wrinkled and flaccide, and more tending toward a Plane, then in young persons, who have a smooth pro∣tuberant, Cristalline Humor, well adapted to Sight.

The Seat of this Humor is placed near the center of the Eye, * 1.57 confining above upon the Aqueous, and below upon the Vitreous Humor, which re∣ceiveth a great part of the lower convex Region of the Cristalline Humor in its concave Surface; so that the Cristalline Humor being not exquisitely seated in the middle of the Eye, is excentrick to it, if it be strictly taken in reference to its whole Globe, and the Humor is more concentrick in its an∣terior Surface to the Cornea, to which it is excentrick, as to its lower Region.

As to the transparency of this Humor, * 1.58 it is a matter of as much difficulty as pleasantness, to know the cause and manner of it, which dependeth up∣on the Compage and Contexture of its various parts; and Bodies are more or less transparent, as they consist of more or less rare Particles: And opace Bodies are made up of many Dense parts, so closely conjoyned, that they admit few or no thin airy, or aethereal Particles, into their ambient Region, and more inward Recesses; whereupon Bodies become more or less dark, as

they are with divers degrees of Density, which hinder the reception of Light, into their more compacted substance.

Learned Gassendus is of a different Sentiment, affirming Bodies are more or less transparent, as their parts have greater or fewer empty spaces, receptive of Rays of Light, and are more or less Opace, as they are com∣pounded of more or less dense Atomes, giving a resistance to, and making reflexions of the beams of Light, in which I will give you the words of the Author, making this inference after a discourse of transparent and opace Bo∣dies: Sequitur denique ut inter spacium summe perspicuum, & corpus summe opacum, sunt omnes gradus perspicuitatis & opacitatis intermedii, id circo in his gradibus, nullum sit corpus adeo perspicuum, cui non mista aliqua opacitas, nullum adeo opacum, cui non aliqua perspicuitas, utpote tanquam existentibus inanibus spatiolis, nunc pluribus, nunc paucioribus Corpusculis quae trajecturis radiis obsi∣stant illosque repellant. This Opinion is founded in the empty spaces of Bo∣dies, which being more or less numerous, do constitute greater or less de∣grees of transparence, as receptive of more or less influxes of Light; The Learned Author farther illustrateth this assertion with divers instances; Ait ille, cogita quam liceat facilius explicam negotium per interpositionem inanis, usi sumus superius, cum de inani disserimus, similitudine tritici quod laxius, pressius∣que cupit, majorem minoremque locum, in medio. Aut quemadmodum vellus ma∣nu diducentes, atque comprimentes, concipimus aerem rarefacere & addensari ac raritatem fieri, cum pili prius viciniores detrahentur a seinvicem, locaque in∣tercipiantur, plura autem aut ampliora in quibus lanae nihil sit, densitatem vero, cum partes priùs distantiores magis ad se mutuo accedant, locaque pauciora, mi∣norave intercipiantur.

The Renowned Authors meaning in this (as I suppose) that the grains of Corn, as they lye more close or loose in the Bushel, are more or less extend∣ed, and affected with greater or less degrees of Rarity and Density, as they have more or less empty spaces; And so proportionably a Fleece of Wooll hath more or less Rarity, and Density, as the Hairs are more united to, or distant from each other; and as they lye more loose or compressed, have more or less intercepted spaces, which I humbly conceive, are not mere va∣cuities (as the Learned Author will have it;) by reason the intercept∣ed spaces found in the loose position of Corn, and the Interstices in the con∣texture of Wooll, are not (as I conceive) destitute of all Bodies, but are filled with subtle Particles, as little Cells of Air, out of which it maketh a quick retreat into that common ambient Receptacle, when the grains of Corn, or hairs of Wooll run close together by a compressive force.

And after I have given Great Gassendus his more profound Notions of transparent Bodies, * 1.59 I take the boldness humbly to offer some of mine own meaner Sentiments, wherein I apprehend much of Transparency to proceed from the different contexture of Bodies, which are more or less pellucide, as they consist of many thicker or thinner Laminae, placed one above another, and joyned so near together with most curious Commissures, that they seem to constitute one entire substance, by reason we are not able to discern the edges of the Commissures in the Compage of Gemms, Diamonds, Glass, and other transparent Bodies, which do admit a splitting, according to their Grain, and Ducts of the flakes in Glass, Diamonds, &c. and cannot be well and equal∣ly parted cross-ways against the Grain and Ducts of the Commissures, but they will irregularly break into odd pieces, and defeat the design of the Ar∣tificer.

And it being granted, that Jewels, Diamonds, Cristal, and common Glass, are made up of numerous thin, and thicker conjoyned Laminae, and are thereupon more or less clear and transparent, as the greater or less propor∣tion of lucide Particles (which being subtle aethereal Bodies) can easily insi∣nuate themselves between the Commissures of the Flakes, and give a greater or less brightness to the whole laminous Body, as it is composed, and made up of more or less thin Shells, between whose joynts the beams of Light do more or less display themselves, and render their Bodies more or less Diaphanous: so that this conjecture of Transparency may have probability in solid Bodies, as framed of divers thin Plates; but the account may be diffe∣rent of these solid and fluide Bodies, as having many minute Particles, which may be easily separated, and have numerous little Pores, filled with more subtle Airy, or Aethereal Particles, which will easily insinuate into the in∣ward Recesses of fluide Bodies, and pass through to the ambient parts, so that a Body less subtle then that of Air, as the smoak of Tobacco, will be transmitted through the pores of Water, which hath been often made appear to vulgar Eyes: whereupon liquid Bodies, consisting of innumerable minute Particles, are every where beset with small Pores, replenished with airy Par∣ticles, into which Rays of Light being freely darted, do give it a beautiful Transparency, which is more or less visible, as the Liquor is more or less Lympide, caused by greater or less defaecation, from gross and earthy Parti∣cles, rendring Liquors more or less turbid; whereupon they are receptive, of more or less irradiations of Light. * 1.60

The Cristalline Humor of the Eyes is formed of the transparent fluide Par∣ticles of the feminal Matter, into whose numerous Pores, fraught with thin airy Atomes, the beams of Light may make many arrangments, every way disposing them to Transparency: and though afterward this Cristalline Hu∣mor, impregnated with saline Particles, groweth somewhat more solid, yet it retaineth still more spaces, replenished with thin volatil substances, capable to receive the transmissions of Light, which by making themselves pas∣sages every way, do dispose the more solid Particles after a manner re∣quisite to the constitution of a transparent Body: An instance may be given, That Silver in Aqua-fortis, or Lead in Spirit of Vinegar, have by that solution, their Particles reduced to a more fluide Form, and their substance before Opace, is so disposed of by Art, as to make a diaphanous Solution; but if one pleaseth to make transparent Cristals, it may be observable, that Bodies once fluide, and highly affected with Rays of Light, are so ordred, that though they grow afterward concre∣ted, yet they retain much of the First impression of transparent Bodies, as may be seen in Cristals, Ice, and also in Diamonds, and other Jewels, which I conceive are originally fluide Bodies, in solutis principiis, and af∣terward are coagulated into more solid Bodies by their petrescent Li∣quors.

The Vitreous Humor is so called, because it resembleth Glass melted by an intense Fire, both in Consistence and Transparence, and is somewhat more fluide then the Cristalline Humor, and more solid and viscous then the Aqueous.

Its situation is in the lower region of the Eye, and containeth the Segments of the lower Region, belonging to the Cristalline Humor, in its Sinus.

The Figure is Semilunary, Concave in the upper Surface, as having greater dimensions about the middle, and terminating into Two obtuse

Cones. This Humor is Convex in the lower Surface, and its whole Perime∣ter is encircled with a fine transparent Tunicle, called Vitrea, severing it from the Cristalline Humor, and boundeth its more fluide Particles, and se∣cureth it from intrenching upon the neighbouring parts.

The Vitreous Humor deriveth its first production from seminal Liquor, which consisting of thin and fluide Particles, hath a loose Compage, easily receptive of Light, whose subtle aethereal Particles make many arrangments through its ambient parts, and more inward Recesses, giving it a clearness and Transparence, which is endued with a power to receive the Visory Rays, and transmit them to the Retina.

Notes

• * 1.1

  A description of the Eye.
• * 1.2

  The seat of the Eyes.
• * 1.3

  The Eye-lids.
• * 1.4

  The lower Eye-lid.
• * 1.5

  The upper Eye-lid.
• † 1.6

  T. 15. F. 1. u u.
• * 1.7

  The Elevator of the upper Eye-lid.
• * 1.8

  The Orbicular Muscle of the Bye lid.
• * 1.9

  The Semicir∣cular Muscles of the Eye. The upper Se∣micircular Muscle.
• * 1.10

  The lower Semicircular Muscle.
• * 1.11

  The actions of the Semicir∣cular Muscles.
• * 1.12

  The Super∣cilia.
• * 1.13

  Excretory Vessels ari∣sing about the roots of the Cilia.
• * 1.14

  The divers kinds of Ex∣cretory Ves∣sels relating to the Glands of the Eyes.
• * 1.15

  The Glands seated in the angles of the Eyes.
• * 1.16

  Ducts passing out of the Glandula La∣crymalis into the Nostrils.
• * 1.17

  The use of the Glands of the Eyes.
• * 1.18

  The Figure of the Eye.
• * 1.19

  The Muscles of the Eye.
• † 1.20

  T. 15. F. 3. a a.
• * 1.21

  The first Mus∣cle of the Eye, is called Su∣perbus.
• † 1.22

  T. 15. F. 3. c. The second is called humilis: The third is Adductor.
• † 1.23

  T. 25. F. 3. d.
• † 1.24

  T. 25. F. 3. e.
• * 1.25

  The fourth Muscle.
• * 1.26

  The fifth or less oblique M••scle.
• † 1.27

  T. 25. F. 3. f.
• † 1.28

  F. 2. g. The sixth and larger oblique Muscle of the Eyes.
• * 1.29

  The first Coat of the Eye is called Adnata.
• † 1.30

  T. 25. F. 6. b.
• * 1.31

  The Cornea.
• † 1.32

  F. 6. a a a.
• * 1.33

  The Figure of the Cornea.
• * 1.34

  The Surface of the Cornea.
• * 1.35

  The origen of the Cornea.
• * 1.36

  Precious Stones are originally fluid.
• * 1.37

  The Geome∣trical Figures of precious Stones.
• * 1.38

  The first rudi∣ments of Transpa∣rency.
• † 1.39

  T. 25. F. 7. a, The Third Tunicle of the Eye called Ʋvea.
• * 1.40

  The seat of the Ʋvea.
• * 1.41

  The Tunicle of the Eye, called Iris, from var••ety of colours.
• † 1.42

  F. 25. F. 7. b. The Pupil of the Eye.
• * 1.43

  The various dimensions of the Pupil.
• * 1.44

  The motion of the Pupil.
• † 1.45

  T. 25. F. 7. cc. The Processus ciliares.
• * 1.46

  The Origen of the Preces∣sus ciliares.
• * 1.47

  The First use of the ciliary Processes.
• * 1.48

  The Second use of the ci∣liary Pro∣cesses
• * 1.49

  The Tunicle of the Eye. called Retina.
• † 1.50

  T. 25. F. 9. dd. The watry Humor of the Eye.
• * 1.51

  The Configu∣ration of the Aqueous Hu∣mor of the Eye.
• * 1.52

  The use of the watry Humor of the Eye.
• † 1.53

  T. 25. F. 9. tt. The Cristal∣line Humor of the Eye.
• * 1.54

  The Cristal∣line Humor is not properly fluide.
• * 1.55

  The Mem∣brane of the Cristalline Humor.
• * 1.56

  The Figure of the Cristalline Humor.
• * 1.57

  The Seat of the Cristal∣line Humor.
• * 1.58

  The Transpa∣rency of the Cristalline Humor.
• * 1.59

  The Authors Opinion of Transparency.
• * 1.60

  The formati∣on of the Cristalline Humor.