ON THE ESSENTIAL ORGANS OF SIGHT. 7-! 9 



troduction of course causes the immediate evacuation of the fluid 

 contained in the anterior chamber, and the dropping or collapsing 

 of the cornea, which assumes a rough and shrunken appearance. 

 In a few hours, however, it resumes its normal condition, the 

 secretion of the humor having taken place, and the wound of the 

 cornea being closed. 



Compresses of cold water, and the application of a weak solu- 

 tion of atropine will obviate severe symptoms. 



C. — Staphyloma. 



This designation applies to a deformity or distension of the 

 cornea, consisting in its protrusion beyond its normal and sym- 

 metrical convexity. It varies in shape, and may be round or 

 pointed. It is very common in dogs, especially in young ones, 

 and if not discovered and attended to in its first stage becomes 

 very rebellious to treatment. If overlooked and neglected ulcera- 

 tion of the cornea and destruction of the eye is certain. 



Cauterization, with nitrate of silver, the ligature, and complete 

 excision with the scissors are recommended, but the chances of 

 success depend on the length of time it has existed and the size 

 it has attained. 



D. — Cataract. 



The opacity of the crystalline lens, or that of its capsule, or 

 that of the humor of Morgagni, or of these three conjointly, pro- 

 duces loss of sight, and for its re-establishment the operation 

 called " of the cataract " is, in some exceptional cases, attempted 

 on horses and dogs. 



The object in view is the extraction of the opaque lens; its 

 division into fragments that may be resorbed ; or its dislocation 

 from its normal position. It is not often performed in veterinary 

 practice, but successful attempts have been credited to Vatel, La- 

 fosse and others, while still others, as Gohier, Brogniez, H. Le- 

 blanc, Haubner, Hertwig and Hering have reported their results 

 as sometimes successful and sometimes otherwise. 



The animal is to be placed in the deciibital position, and the 

 dilatation of the pupil is to be obtained by the application of a 

 solution of sulphate of atropia or extract of belladonna. 



Among the difficulties connected with this operation is the 

 peculiar anatomy of the globe of the eye, which by the action of 



