68 DISEASES OF THE HORSE. 



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 eje. 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 ac- 

 counts for the shying and starting, when one eye is im- 

 perfect or diseased. If one 'eye only be altogether de- 

 stroyed, the horse will not shy or start, but will be a use- 

 ful 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.) Amaurosis. — This is the same disease that Mil- 

 ton was affected with, and was called by him " drop se- 

 rene." 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 eye of either man or horse, and is ushered in by 

 weeping and partial closure of the eyelids. A thin film 

 or scum will soon be observed .to spread over the whole 

 of the front of the eye. This condition will pass off for 

 a week or two, and then return with increased violence 

 until the sight will be entirely destroyed. Spots will be 

 seen between each attack, deep in the eye, gradually in- 

 creasing in size, till the nerve of sight is totally destroyed. 



Causes. — Inflammation affecting the brain, tumors, or 

 bone pressing upon the optic nerve. 



Treatment. — Doubtful of cure. Small doses of strych- 

 nine may be tried to restore the sensibility of the optic 

 nerve, or colchicum may be used. (See Medicine.) 



