108 



Veterinary Elements. 



The vitreous humor, a jelly-like mass fills up the bulk of 

 the eye, and is located back of the lens, once destroyed 

 is never reproduced. The inner coat, retina, is the dis- 

 tribution of the optic nerve (nerve of sight) and is con- 

 sequently the most important structure in the eye. 



The choroid coat lines 

 the sclerotic, at its front 

 portion is attached a 

 muscular curtain, the 

 , x iris, located in front of 

 the crystalline lens. 

 This curtain (iris) is 

 pierced in its center by 

 an opening, which varies 



DIAGRAM OF A HORSE'S EYE. shape in the different 

 A sclerotic coat. X cornea, B cho- animals and is known 



roidcoat. I Iris. C Retina. D Optic ,, ., mi . 



nerve. V- Vitreous humor. L-Crystal- as tne PUP 11 - IhlS Open- 

 line lens. H-Aqueous humor. in g j g flirted Or CO11- 



tracted, by two sets of muscular fibres, according to the 

 amount of light the sensitive structures of the eye are 

 able to take in. The color of the eyes is due to the iris, 

 in most horses it is of a brownish yellow tint, in others 

 white or grey, when the latter color, the horse is said to 

 be wall-eyed; at the upper border of the pupil of the 

 horse little black sooty looking dots are seen, these are 

 the corpora nigra, they are said to absorb rays of light. 

 The outer covering, sclerotic coat, is hard and fibrous, 

 and receives the attachment of the muscles of the eye- 

 ball, it is opaque; at its front portion is inserted the cor- 

 nea (watchglass), a delicate transparent membrane made 

 up of layers of cells; between these layers as a result of 



