146 NAVIN ON THE HORSE. 



CATARACT. 



There are two species of this difficulty; one being a dis- 

 eased condition of the lens of the eye, and the other tlie form- 

 ation of a false membrane over the lens, either of which will 



produce blindness. 



>Sym/;to5.— Cataract will often not be discovered, especially 

 by a careless owner, until a difficulty of vision is made obvi- 

 ous by the horse exhibiting the usual indications of blindness. 

 But it will usuallv be found to commence by a speck, of a 

 radiating appearaiace, like the rays of the sun, formmg on 

 the lens of the eye, seen through the pupil, either near the 

 center of it, or at the upper or lower edge. This speck may 

 continue to increase until it entirely covers the pupil, causing 

 it to appear of a uniform whitish color, and causmg complete 

 iblindness; or it may never advance further than a mere spot, 

 more or less obstructing vision, as it may happen to be near to 

 ■or remote from the center of the pupil. . , , . 



A cataract may be distinguished from amaurosis, (palsy of 

 ihe nerve of sight), by the permanently dilated and bnght 

 .appearance of the pupil in the latter, and the speck of white, 

 ,or entire white, within the pupil, as described m cataract. A 

 ■ cataract may appear only in one eye, or in both. ^ 



Causes.-Any thing that will give rise to a chronic (con- 

 tinued) irritation of the eye may produce cataract., irritation 

 from exposure of the eye to intense light is very liable to 



• cause it. 



Treatment.— Yeicvm^ry surgeons do not seem to agree very 



perfectly as to the curability of cataract, or, rather, as t^ the 



■propriety of operating for it. We have no faith m any thing 



but an operation for this difficulty, unless it be discovered 



when a mere speck has formed on the lens, when its growth 



might possibly be stopped by putting the horse on grass m a 



shady or wood pasture, and giving him what is called altera 



live treatment-such as any of the alteratives named under 



that head, in the materia medica part of this work; and, at 



