OPHTHALMOLOGY FOR 

 VETERINARIANS 



CHAPTER I 

 ANATOMY OF THE EYE 

 "From a point of view of comparative anatomy, an 

 eye is any part of an animal body which responds 

 more readily than other parts to the special stimulus 

 of hght, or whose activity is specially excited by the 

 impact of Hght rays."— Cew/wry Dictionary. 



In the low forms of life the eye-spots or eye-points, 

 as they are called, differ greatly in number. They 

 are rudimentary eyes, and consist in many cases of 

 simple pigment spots sensitive to light, and may be 

 situated anywhere on the body. 



In insects proper, crustaceans and arachnidians, the 

 eyes are well developed and are either simple or com- 

 pound. They are usually two in number, but may be 

 four, six, or eight. Crustaceans, as a rule, have a single 

 pair, which stand out from the head like a cherry upon 

 a stem. 



In describing the anatomy of the eye, that of the 

 highest order of the animal kingdom will be consid- 



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