80 DISEASES OP THE HOESE. 



the conjunctiva, which is reflected from them over the ante- 

 rior surface of the eyeball. 



(2.) The globe of the eye is not exactly round, for it is 

 more like a segment of a smaller circle put into a greater 

 one. 



(3.) The clear portion of the eye is called the cornea, and 

 forms a portion of the globe. 



(4.) The sclerotic coat is what is called the white of the 

 eye ; and just back of it is what is called the choride coat 

 of the eye. And immediately within this choride coat is 

 placed the retina, or the expansion of the optic nerve, or 

 the nerve of sight. 



(5.) The humors of the eye occupy the anterior chamber, 

 as well as pass into the posterior. The iris floats in this 

 humor, and behind it will be found the magnifying lens of 

 the eye. This is a double convex, and is placed in the 

 centre of vision, and fronting the next, or vitreous humor 

 of the eye. This humor is enclosed in a capsule, called the 

 hyaloid membrane. The eyes of the horse are so placed in 

 his head, that he, at the same time, sees different objects 

 with each eye, which peculiarity accounts for the shying 

 and starting, when one eye is imperfect or diseased. If 

 one eye only be altogether destroyed, the horse will not shy 

 or start, but will be a useful animal. This is the reason 

 why cataract on the eye of a horse had better be let alone, 

 as any imperfect sight will make the horse dangerous to 

 drive, objects being seen in distorted form. Better the eye 

 be completely destroyed than partially so. 



(1.) Amatjbosis. — This is the same disease that Milton 

 was affected with, and was called by him " drop serene." 

 It is a complete or partial blindness from loss of sensation, 

 or feeling of the optic nerve. 



Symptoms. This is the most serious disease affecting the 



