414 Veterinary Medicine. 



tion of a germ as the last item in the chain of causes is presump- 

 tively true. 



Parasitism. Willach claims that many cases are directly due 

 to parasites in the eye. In 19 affected eyes he found one young 

 filaria, a number of rhabditis (?), i cysticercus, and a number of 

 distomata. I^eider also found round worms in such eyes. Mayer 

 and Dexler examined a number of cases, using the centrifuge on 

 the liquids of the e}^, without in any case finding such parasites. 

 It may be assumed that the presence of embryo worms may rouse 

 a latent predisposition into activity, but they cannot be adduced 

 as active causes in the vast majority of cases. 



Symptoms. These vary with the severity of the attack. In 

 some cases there is high fever while in others this may be absent , 

 yet a lack of vigor and energy bespeaks a general constitutional 

 disturbance. The attack is sudden with marked local irritation, 

 photophobia and lachrymation. The eyelids are closed some 

 times so firmly as to suggest blepharospasm, and if opened the 

 pupil is seen to be contracted.' The affected eye is retracted and 

 appears smaller, the conjunctiva is the seat of diffuse redness and 

 swelling, and there is a bright red peri-corneal injection, occupy- 

 ing the anterior portion of the sclera. The outer zone of the 

 cornea is already the seat of a bluish white opacity, the surface 

 appearing dull and as it were smeared with oil. The centre of 

 the cornea may be opalescent but not so obscure as to prevent 

 examination of the interior of the eye. In a few days the outer 

 margin of the cornea may show vascularity, and the aqueous 

 humor a certain degree of turbidity. The iris if still visible is 

 seen to be swollen and rigid, and to have parted with some of its 

 lustre, assuming a grayish or lighter color owing to congestion 

 and exudation. The pupil is usually contracted and dilates only 

 sluggishly and imperfectly in darkness or under the action of 

 atropia. The iris arches forward more than is normal and may 

 even approximate and adhere to the back of the cornea. Bayer 

 noticed that in a partial albino (watch eye) the iris becomes sul- 

 phur yellow. The anterior chamber of the aqueous humor usually 

 shows a grayish yellow sediment which in severe cases may fill 

 one-third or even one-half of its depth. This may be grayish 

 white flocculi of lymph only, or it may be colored with blood 

 or in suppurative cases by pus. In the first day of its appear- 

 ance this may be diffused through the humor, but from the fifth 



