332 



THE EYE. 



B 



FlG - 98 A of the cornea 



and measur- 

 ing about one 

 inch. The 

 axes of the 

 eyes are par- 

 allel to each 

 other, "but not 

 to that of the 

 bony orbit. 



The eye 

 is a hollow 

 sphere com- 

 posed of a 

 membranous case, and 

 four refractive lenses or 

 media of light. The 

 case consists of three 

 coats or membranes, an 

 outer, middle and inner, 

 called the sclerotic, cho- 

 roid, and retina. 



Tunica Sclerotica, 

 (Fig. 98, A,) (twtypoj, 

 hard.) Dissection. Clean the ball of all its attachments, 

 which is best done with the scissors, while the eye rests in 

 a shallow dish of water. 



This membrane forms the whole of the outer coat of the 

 eye, except its front part, which receives the cornea. Its 



FIG. 98, A represents a section of the Eyeball. 1 Upper lid. 2 2 Meibo- 

 mian glands. 3 Reflection of tunica conjunctiva. 4 Cornea. 5 Anterior 

 chamber of the aqueous humor. 6 Pupil. 7 Iris. 8 Crystalline lens. 9 

 Ciliary processes. 11 Canal of fontana. 12 Canal of petit. 13 Section of the 

 vitreous humor. 14 Central artery of the retina, passing through the vitreous 

 humor. 15 Optic nerve, a Sclerotic coat, b Choroid. c Membrane of 

 Jacobs, d Ptetina. e Hyaloid membrane. 



FIG. 98, B represents the Choroid coat, or second tunic of the Eye. a 

 Choroid. 6 b Ciliary nerves, c Long ciliary artery, d Ciliary ligament, e 

 Iris, showing its two sets of fibres the circular and radiating. / Pupil. 



