126 NON-SPECIFIC OR GENERAL DISEASES 



a transparent jelly-like substance that fills all the cavity of the 

 eye posterior to the lens. The aqueous humor is a liquid, con- 

 tained in the anterior and posterior chambers of the eye in front 

 of the lens. This fluid separates the iris from the front of the 

 lens. 



Examination of the Eye. — In examining and treating the 

 eye we should avoid rough and hasty manipulation. The animal 

 should be approached slowly. It is best for the attendant who is 

 familiar with the animal to hold it for the examiner. It is 

 advisable on approaching the animal to stroke its face, and in 

 the horse to brush its foretop away. The hand should be carried 

 slowly to the front of the eye, and the lids separated with the 

 fingers and thumb if we wish to obtain a better view of the cornea. 

 In cattle the best view of these parts can be obtained by taking 

 hold of the nose and lifting the head. It is impossible to make 

 a satisfactory examination of the eye outside of the stable Avhere 

 the light is coming from all directions. The most satisfactory 

 conditions under which a general examination can be made is 

 to stand the animal facing a transom, window or open door. We 

 may then look directly into the eye and note the condition of the 

 different refracting media. 



The lens should appear transparent and free from scars. The 

 aqueous humor free from any cloudiness or precipitate. Both 

 pupillary openings should be the same size, and not too small 

 or too large in the bright light. As we look through the pupil- 

 lary openings, both the lens and the vitreous humor should refract 

 the light properly and not appear white or greenish-white in 

 color. The color of the iris should be noted. If it lacks lustre 

 or appears dull, this may indicate an inflammation. In periodic 

 ophthalmia in horses the iris loses its lustre and becomes a rusty- 

 broAvm color. It is very important to note this change in the 

 appearance of the iris. We should note, in addition, the expres- 

 sion of the animal's face, the position of the ears and eyelids and 

 manner of the walk. Horses that have defective sight may show 



