31 S MEMBRANA NICTITANS. 



of nux vomica mixed in the feed. The author has never wit- 

 nessed any beneficial results from bleeding, although it is re- 

 commended by some writers. 



INFLAMMATION OF THE MEMBEANA NICTITANS. 



This affection is commonly called the haw, or hooks. The 

 membrane affected is somewhat triangular in form, concave on 

 the inner side, and convex externally. It is mainly composed 

 of cartilage, or gristle, and is situated between the eye ball and 

 the side of the orbit, at the inner corner of the eye. In a per- 

 fectly healthy condition but a very small portion of this mem- 

 brane is visible ; but when in a state of inflammation it bulges 

 out very considerably. A portion of the membrane covering 

 it becoming, as it were, folded upon itself presents a hook- 

 like appearance, which has been regarded by farriers as a 

 foreign substance, to which the name of "hooks" has been 

 given, and its removal with the knife recommended by them. 

 It so happens, however, that this membrane is placed in the 

 eye, or attached thereto, to serve a useful purpose : that of 

 cleansing the eye from dirt, or any foreign substance that may 

 chance to get into it, which is accomplished by throwing it 

 over the ball of the eye, and removing any obstruction. In- 

 jury must result from cutting away any portion of this mem- 

 brane, as its function is in part destroyed ; since the animal 

 can no longer throw it over the ball of the eye with the same 

 facility as before the operation was performed. In point of 

 fact, wherever the hooks, as they are called, are cut out, it will 

 be observed that whenever any foreign substance gets into the 

 eye, the animal makes a spasmodic effort to throw this mem- 



