VETERINAKY OPHTHALMOLOGY. 1§1 



it will recur again and again and in the saiiue eye um- 

 til total loss of sight ensues. These attacks may oc- 

 cur at intervals of a mouth or so, but they show no 

 relation to any particular phase of tlie moom, as tihe 

 name would lead one to suppose. These recurrences 

 are determined, more lilcely, by some periodicity of 

 the system. From five to seven or eight attacks usu- 

 ally suffice in resulting blindness, and then the secorad 

 eye is liable to attack with the same result. Between 

 the attacks some latent symptoms tell the story, ajnd 

 these symptoms become more marked with each suc- 

 cessive attack. Even after the first attack there can 

 be seen a bluish ring around the corneal margin, tlie 

 eye therefore seeming smaller ; and after several attacks 

 it is smaller frorii atrophy. The upper eyelid, in place 

 of presenting a uniform continuous arch, has about 

 one-third from its inner angle an abrupt bend caused 

 by the contraction of the levator muscle. The pupil 

 is '(^ontracted except in advanced cases, where, with an 

 opaque lens, it will be widely opened, dilated. The 

 animal will carry his ears erect and forward to com- 

 pensate for his waning vision. Now, this is a general 

 picture, but that the attacks vary with different cases 

 must be remembered. The recurrence, however, is 

 characteristic, and all alike lead to cataract and intra- 

 ocular effusion, giving rise to T +, with pressure on 

 the retina and resulting blindness. The prevention of 

 this disease is the great object, and to accomplish this 



