The workes of that famous chirurgion Ambrose Parey translated out of Latine and compared with the French. by Th: Johnson

CHAP. VI. Of the Muscles, Coats and humors of the Eye.

THere are sixe muscles in the eye, of which foure performe the foure direct motions of the eye: they arise from the bottome of the orbe, and end in the midst of the eye encompassing the opticke nerve. When they are all moved with one endevour, they draw the eye inwards. But if the upper only use its action, it drawes the eye upwards; if the lower, downewards; if the right, to the right side; if the left, to the left side.

The two other muscles turne the eye about, the first of which being the longer and slenderer, arises almost from the same place, from which, that muscle arises which drawes the eye to the right side to the greater corner. But when it comes to the ut∣most part of the inner angle, where the Glandula lachrymalis is seated, it ends in a slender Tendon, there peircing through the middle membrane which is there, as through a ring; from whence it presently going backe is spent in a right angle towards the up∣per part of the eye, betwixt the insertions of those 〈◊〉〈◊〉 muscles, of the which one draws the eye upwards, the other directly to the outward corner, as it is observed by Fallopius or rather, which I remember I have alwaies observed, they turne between the muscles which move the eye upwards, and to the inner corner.

This fifth muscle when it is drawne in towards its beginning, so drawes the eye with its circular tendon, that it carries it to the greater corner.

The sixt muscle is contrary to that; for it hath its originall from the lower part of the orbe at a small hole, by which a nerve of the third conjugation passes forth; and being that it is most slender, whilest it ascends transversely to the outward corner, it involves the eye so also, that it is inserted in it by a small Tendon, so that the Tendons of them both are oftentimes taken but for one. That thou maiest truely and accurately observe this anatomicall description of the eye; the eye must not be pluct out of its orbe, but rather the orbe it selfe must be broken and separated.

For thus thou shalt certainlie and plainelie see the forementioned originall of the muscles. For the five coats, the first which is first met with in dissection, comes from the pericranium, and is extended over all the white of the eye, even to the 〈◊〉〈◊〉 or Rain-bow. The duty of it is to strengthen, bind and containe the eye in its orbe, where∣fore it had the name Coniunctiva, others call it Adnata, or Epipephycos.

The second is called the Cornea, because it resembles a horne in colour and con∣sistence; this coat differs and varyes from it selfe, for in the forepart, as far as the Iris goes, it is clear and perspicuous, but thick & obscure in the binde part, by reason of the diverse polishing. On the fore-part it is dense that it may preserve and containe the Christalline and waterish humor, but withall transparent so to give the object a freer passage to the Chrystalline. It hath its originall from the Crassa meninx, proceeding forth from the inner holes of the orbe of the eye, for it compasses the eye on every side.

The third is called the Vvea or Grapy coat, because in the exterior part it represents the colour of a black grape; it arises from the Piamater, and encompasses all the eye, except the pupilla or apple of the eye, for here being perforated, it adheres to the hor∣ny coate by the veines and arteries which it communicates to it for life and nourish∣ment. But when it arives at the Iris, then forsaking the Cornea, it descends deep into the eye, and in some sort is turned about the Christalline humour, to which also it most firmely adheres, so bounding the waterish humor, and also prohibiting that the Albugineous humor doe not overwhelme the Christalline. This grapy coate is as it were dyed on the inside with divers colours, as black, browne, blew, or green like a raine-bow, and that for these ensuing benifits.

The first is, if that it had beene tinctured with one colour, all objects would have appeared of the same colour, as it comes to passe when we looke through green or red glasse. But it must be coloured, that so it may collect the spirits dissipated by the Sunne and seeing.

Thirdly it was convenient it should be painted with infinite variety of colours for the preservation of the sight. For as the extreame colours corrupt and weaken the sight, so the middle refresh and preserve it, more or lesse as they are neerer, or further remote from the extremes. It was fit it should be soft, that so it might not hurt the Christalline humor uppon whose circumference it ends; and perforated in the part objected to it, least by its obscurity it should hinder the passage of the objects to the Christalline, but rather that it might collect by its blacknes as a contrary, the great and as it were diffused varietye of colours, no otherwise than wee see the heat is strengthened, by the opposition of cold; some call this coat Choroides, because it is wo∣ven with many veines and arteries, like the coat Chorion which involves the infant in the wombe.

Now followes the fourth coate called Ampiblistroides or Retiformis, the Net-like coate, because proceeding from the opticke nerve dilated into a coate, it is woven like a net with veines and arteries which it receives from the grapy coate, both for the life and nourishment both of its selfe, as also of the glassie humor which it encompasses on the back part. The principall commodity of this coate is, to perceive when the Christalline humor shall be changed by obiects, & to leade the visive spirit instructed or furnished with the faculty of seeing, by the mediation of the glassie humor, even to the Christalline being the principall instrument of seeing. It is softer than any other coate, least the touch of it should offend that humor. Wherein thou wilt admire the singular order of nature, which as in other things it passes not from one extreme to a∣nother unlesse by a Medium, so here it hath not fitted the hard horny coate to the soft humors, but by interposition of divers media of a middle consistence. For thus after the harder coats Adnata and Cornea it hath placed the Grapy coate, by so much softer then these two, as the Net-like coat is softer then it, that thus it might passe from ex∣treme to extreme as it were by these degrees of hardnes and softnes.

The fifth and last coate is called Arachnoides, because it is of the consistence of a spiders web. And wee may well resemble this coate, to that skin of an union which exceeds the other in clearnesse, whitenesse and thinnesse. This Araneosa or Cobweb∣like coate encompasses the Christalline humor on the fore fide, peradventure that so it might defend it, as the chiefe instrument of seeing, if the other humors should at any time bee hurt. It hath its originall from the excrementitious humidity of the Crystalline humor, hardened into that coate by the coldnes of the adjacent parts; absolutely like the thin skin which encompasses the white of an Egge.

The first humor of the eye is called the Aqueus or waterish, from the similitude of water; it is seated betweene the transparent part of the Horny coate, the portion

of the Christalline humor lying towards the apple of the eye, and that reflection of the Grapy coate which comes from the Iris to the circumference of the Chry∣stalline humor, that filling the empty space it may distend the Cornea, and so hinder the falling thereof upon the Chrystalline which would spoyle the sight; as also that by its moisture it might hinder the drying of the Chrystalline humor. Peradventure it is made of the whayish humor sweating out of the vessells of the coats, having their orifices for the most part in that place, where this waterish humor resides. The second humor and middle most in scituation is called the Chrystalline because it imitats Crystall in the brightnesse and colour; if so be that we may attribute any colour to it. For indeed it was fit that none of the three humors should be tinctured with any colour, as those which should be the instruments of sight, lest they might beguile us in seeing as Red and greene spectacles doe; for that is true which wee have read written by the Philosopher; That the Subject or matter ap∣pointed for the reception of any forme should want all impression thereof. Hence Nature hath created a formelesse matter, the humors of the eyes without colours, waxe without any figure, the minde without any particular knowledge of any thing, that so they might be able to receive all manner of formes. The figure of the Crystal∣line humor is round, yet somwhat flatted on the foreside, but yet more flatted behinde that so the objects might be the better retained in that, as it were, plane figure, and that they might not fly backe as from a Globe, or round body, in which they could make but short stay; lest it might be easily moved from its place, by the force of any thing falling or hitting against it, because that body which is exactly round touches not a plane body but onely in a point or pricke. Halfe this humor swims in the Glassy humor, that so it may be nourished from it by transposition of matter; or rather (seeing it is encompassed on every side with the fist coate, that the matter cannot easily be sent from the one into the other) by the benefit of the vessels pro∣duced even unto it as well by the Net-like coate, as by the Grapye; but it is filled with a bright spirit on the forepart, which lyes next to the waterish humor, and the space of the Apple of the eye.

Of which thing this is an argument, that as long as a man remaines alive, wee see the eye every way full, and swollne, but lanke and wrinkled when he is dead; besides also one of the eyes being shut, the Pupilla of the other is dilated by the spirit com∣pelled to fly thither. And also for the same cause the horny coate is wrinkled in very old men, and the Pupilla is straitned by the wrinkles subsiding into themselves, which is the cause that they see litle, or not at all; for by age and successe of time the humor is consumed by litle and litle, the implanted spirit vanishes away, and smaller quanti∣tie of spirits now from the braine, as from a fountaine which is also exhausted. The Horny coate at his originall, that is, in the parts next the Iris, seemeth to be very nigh the Crystalline Humor, because all the coates in that place mutually cohere as touching one another, but as it runnes further out to the Pupilla, so it is further di∣stant from the Cristalline. Which you may easily perceive by Anatomicall dissecti∣on, and the operation of touching or taking away a Catarrhact: for whereas a Ca∣tarrhact is seated betweene the horny coate, and Crystalline humor, the needle thrust in, is carried about upwards, downewards, and on every side through a large and free space, neither touching the horny coate nor Crystalline humor, by reason these bodies are severed by a good distance filled with spirit and a thin humor. The use of it is, that it may be like a looking glasse to the facultie of seeing carried thither with the visive spirit.

The third and last humor is the Vitreus the glassie, or rather Albugineous humor, called so, because it is like molten glasse, or the white of an Egge. It is seated in the hind part of the Crystalline humor that so it may in some sort breake the violence of the spirit flowing from the braine into the Crystalline humour, no otherwise than the watry humor is placed on the foreside of the Crystalline to hinder rhe vio∣lence of the light and colours entering that way. This glassie humor is nourished by the net-like coate.

We have formerly spoken sufficiently of the nerves of the eye: Wherefore it re∣maines that we speake of the veines. Some of these are internall, carried thither with

[illustration]

The figure of the eye.

Table 3. figure 1. sheweth the Membranes and humors of the eye by lines drawne after the manner of a true eye.

Figure 2. sheweth the horny coate with a portion of the Opticke Nerve.

Figure 3. sheweth the same divided by a transuerse section.

Figure 4. sheweth the Vvea or Grapy coate with a portion of the Opticke Nerve.

Figure 5. The Grapy coate of a mans eye.

Figure 6. The Horny, Grapy and the Choroides.

Figure 7. The interior superficies of the Grapy coate.

Figure 8. The Posterior part of the horny coate together with the said Net coate separated from the Eye.

Figure 9. The coate of the vitreous or glassy humor called Hyaloides.

Figure 10. Three humors joyned together.

Figure 11. The forward part of the Christalline.

Figure 12, The Christalline humor covered yet with his coate.

Figure 14. The Christalline of a mans eye.

Figure 15, His Coate.

Fig. 16, The watery humor disposed upon the Christalline round about.

Fig. 17. The hairy processes beamingly sprinckled through the foreside of the coate of the glassy humor.

Fig. 18, The foreside of the glassy humor.

Fig. 19. The place of the watery humor.

Fig. 20. The glassy humor containeing or comprehending the Chrystalline.

The explication of the first Figure by it selfe.

a, The Christalline humor.

b, The Glassie humor.

c, The watery humor.

d, The utmost coate called Adnata.

e, The darke part of the horny Tunicle which is not transparant.

f, The Grapy coate called Vvea.

g, The Net-like coate cal∣led Retiformis.

h, The coate of the glassy humor cald Hyaloides.

i, The coate of the Chri∣stalline.

k k, The hairy processes cald Processus ciliares.

l, The impression of the Grapy coate where it departeth from the thick coate.

m, The horny coate, a part of the thick coate.

n n, The fat betwixt the Muscles.

o, The optick Nerve.

p, The Dura meninx.

q, The Pia Mater or thin Meninx.

r r, The Muscles.

The explication of the other 19. figures together.

a 2, 4, 8, The Optick Nerve. b 2, 4, The thin Meninx cloathing the Nerve. c 2, 3, The

[illustration]

thick Meninx cloathing the nerve. d 8. the posterior part of the horny coate. e 8. The coate called Retina gathered together on an heape. f 23. The rainebow of the eye. g 2, 3, The lesser circle of the eye or the pupilla. h 2, 3. Vessels dispersed through the Dura Meninx. i 3, 6, The grapy coate, but i, in the 3. Fig. sheweth how the vessels doe joyne the hard membrane with the grapy coate. k 6. The horny or hard membrane turned over. ll 3. 4, Certaine fibres and strings of vessels, whereby the grapy coate is tyed to the horny. m m 4, 5. The impression of the grapy coate where it recedeth or departeth from the horny coate. n n, 4, 5, 6, 7, The pupilla or apple of the eye. o o, 7, The Ciliar or hairie processes. p 7, The beginning of the Grapic coate made of a thinne membrane dilated, but p, in the 17. figure sheweth the ciliar processes sprinckled through the fore part of the glassie humor. r 9, The bosome or depression of the glassie humor receiveing the Christalline. s 12. 15. The bredth of the coate of the Christalline, t 12, 13, 14, 16, The posterior part of the Christalline humor which is sphericall or round. u 11, 14, 20, The fore-part of the same Christalline depressed x 10, 20. The amplitude of the glassie humor. y 10; 16, 19. The amplitude of the watry humor. z. 19, The place where the glassie humor is distinguished from the watry by the interposition of the Hyalaeides or coate of the glassie humor. & α10, 16, The place where the grap••e coat swimmeth in the watrie humor. & β18. The cavitie or depression of the glassie humor which remaineth when the Christalline is exempted or taken from it.δ 19. the cavitie or depression of the watrie humor made by the same meanes.

the coats of the vessels of the braine; other some externall stretched over the exter∣nall parts of the eye, as the Muscles, and coat Adnata, and by these veines inflamma∣tions and reddnesse often happen in the externall parts of the eye: for which the Venapupis must be opened, and cupping glasses and hornes must be applied to the nape of the necke and shoulders; as in the internall inflammations of the eye the ce∣phalike veine must be opened to avert and evacuate the morbificke humor.

Notes

• The number, site and action of the muscles.
• The 5 coats of the eye.
• Conjunctiva, or Adnata.
• 2. Cornea, or the Horny coate.
• Vvea, or the grapye coate.
• Why the gra∣py coate re∣sembles divert colours.
• 4 Amphiblistr••••∣des or Retifor∣mis, Net: like coate.
• An anatomi∣call Axiome.
• 5 Arachnoides, sive Araneosa, the Coweb∣coa••e.
• The 3 humors of the Eye. 1 Aqueus, or matery.
• 2 Crystallinus, Crystalline.
• A Philosophi∣call Axiome.
• Gal. Cap. 5. lib. 10. de usu part.
• In what place Catarrhacte or suffusion breeds.
• 3 Vitreus, seu 〈◊〉〈◊〉, that is Glassie, or like the white of an Egge.
• The veines of the eye.
• What veines may be opened 〈…〉〈…〉 •…•…ations of the eyes.