138 DR. LEGEAR'S STOCK BOOK. 



THE HAW M KMBRANE NICTITANS. 



The haw is an appendage of the eye placed there by nature 

 for the express purpose of removing any foreign substance, as 

 dust, cinders, sand, or anything that may get on the eyeball and 

 cause pain. The haw, sometimes called "washer of the eye," is 

 supplied by nature to the eyes of all animals and birds, except 

 man and the monkey tribe, which use their hands or paws for 

 that purpose. In the normal restful state of the eye only the 

 thin anterior edge of the haw can be seen at the inner angle of 

 the eye, but when by some cause the eyeball is pushed back into 

 its socket or drawn back by muscular contraction it can be 

 plainly seen projecting over and partially or completely cover- 

 ing the eyeball. AYhen foreign bodies, such as sand, dust, chaff, 

 etc., get into the eye it is projected to push them out, their ex- 

 pulsion being favored by a free flow of tears. In lockjaw, the 

 haw is plainly seen projecting over the eye by the muscular con- 

 traction in each spasm, and it is also seen in a lesser extent in nil 

 painful inflammations of the eye. The projection of the haw, 

 no matter from what cause, is universally known, by people not 

 familiar with the anatomy and diseases of the horse, as the 

 "hooks." 



HOOKS. 



Hooks, like bots, and hollow horn, is not recognized by the 

 Veterinary Profession as a disease. It is no disease, but is sim- 

 ply a symptom of some disease. What is universally known 

 as hooks by most of the horsemen in this country is the projec- 

 tion of the haw (read the article on the haw) partially or com- 

 pletely over the eyeball as the result of some disease. It is a 

 symptom of lockjaw, inflammation, or a foreign substannce in the 

 eye. If due to a foreign substance, such as sand, chaff, cinders, 



