DISEASES OF THE EYE 127 



a deep wrinkle in the upper eyelid when startled or looking 

 directly at an object. Animals that are blind hold the ears in 

 a characteristic position, and may stumble and walk over, or run 

 into objects unless stopped. The ophthalmoscope is a very useful 

 instrument for determining the condition of the different 

 structures of the eyes, when in the hands of persons who are 

 trained in its use. 



Conjunctivitis. — This is an inflammation of the mucous mem- 

 brane lining the eyelids and covering the eyeball. The two 

 forms of conjunctivitis common in domestic animals are the 

 catarrhal and purulent. 



The symptoms differ in the two forms of conjunctivitis. 

 They may be distinguished from each other by the difference 

 in the character of the inflammatory discharge. In the catarrhal 

 form, there is a discharge of tears and the lids are held more or 

 less closed. The mucous membrane is usually brick red in color 

 and swollen. A little later the discharge becomes heavier and 

 adheres more to the margins of the lids. The lids continue ten- 

 der and the inflammation painful. The surface of the cornea 

 may appear white and the blood-vessels prominent, but it is only 

 in the severe cases that inflammation of this portion of the eye 

 occurs. In such cases an elevation in body temperature may 

 occur. This is especially true of purulent conjunctivitis when 

 primarily caused by an infectious agent. In the purulent form 

 the discharge is heavy and pus-like. 



The treatment is both preventive and curative. The first 

 object must be to remove the cause. Irritating gases resulting 

 from stable filth should be remedied by correcting the unsani- 

 tary conditions in the stable. Conditions favoring injury to the 

 eye from foreign bodies, such as chaff and a careless attendant, 

 should be corrected. Animals suffering from the infectious 

 or purulent form of inflammation should be separated from the 

 other animals. Foreign bodies should be removed promptly be- 

 fore they have had an opportunity to set up a serious inflam- 



