CHAPTEE XIV. 

 OPERATIONS UPON THE EYE AND EAR. 



ON THE EYE. 



Ophthalmology, though it has made appreciable progress in vet- 

 erinary practice within a few years, has not yet reached a position 

 corresponding with that which it occupies in human surgery, and 

 probably will not for years to come, if ever. The difference in 

 value and importance between the functions of the organ of sight 

 in the man and in the horse is too measureless to induce or re- 

 quire an equal amount of interest and study in the optical path- 

 ology of the two animals, the human and the equine. It is in- 

 deed, a fact that many of the forms of disease which affect the 

 eye of the horse have not yet been recognized and investigated by 

 students of veterinary medicine. 



For these reasons the contents of the present chapter will be 

 limited to those affections in which, strictly speaking, special sur- 

 gical interference has been so imperatively needed as to compel 

 the attention of scientific veterinarians, by considerations of both 

 duty and interest. 



We shall consider the subject under two principal divisions, 

 or heads, viz., operations, performed on the accessory, and those 

 pertaining to the essential organs of the ocular apparatus. 



1. — Operations Peefoemed on the Accessoey Ocular Oegans. 



On the Eyelids. — These constitute the two cutaneo or mu- 

 cous veUs, which are situated in front of the organ, and are divided 

 into superior and inferior, uniting at their extremities to form the 

 angles or commissures of the eye. Besides these, there is a pecu- 

 liar apparatus situated on the internal or nasal angle, known as a 

 third eyelid, or menbrana nictitans. This is a small cartilage, 

 thinned out on its free border, continued on its posterior portion 

 with the adipose cushion of the eye, and covering it in front, 

 wiping, as it were, its corneal surface, whenever the ocular globe 



