138 



THE DISEASES OF THE HORSE. 



Silver nitrate and other astringent solutions for chronic 

 cases. For doses, see pages 13 to 29. 



CATARACT 



Is opacity of the lens or its capsule. Percivall says it 

 may also be the result of an effusion of an opaque fluid 

 between the two. The opacity may be the result of in- 

 jury or disease. 



Cataract is a common cause of either total or partial 

 blindness. It usually follows ophthalmia, but ophthalmia 

 may attack a cataractous eye. Cataracts are White, black, 

 green, yellow, brown, ash-colored, &c. At first they are 

 soft, but they acquire firmness by age. Some are called 



Fig. 32. Partial Cataract. 



Fig. 33. Complete Cataract. 



bony cataracts. They vary in size from a pin's point to 

 a pea. 



Percivall speaks of both spontaneous and congenital 

 cataracts; D'Arboval of a fluid cataract, which, from its 

 whiteness, is called milky; Gibson of colts being foaled 

 with cataracts or pearls in their eyes. 



Lenticular cataracts grow slowly— 1, 2, or more years. 

 The other kinds may appear in a few days, or even hours, 

 and without any detectible inflammation or previous dis, 

 ease. Capsular cataract is caused usually perhaps by ex, 

 ternal injury. It is easily distinguished, and seems to be 

 absorbable, 



