VETERINARY OPHTHALMOLOGY. 61 



application of a mild irritant, such as calomel or ox 

 mercury, ijng., etc. 



Now for a word on diagnosis of a differential 

 character. In catarrhal conjunctivitis, the injection 

 is general over the conjunctiva, and on pressure, 

 through the lower lid, the injected vessels are seen to 

 move over the sclerotic with the membrane, {i. e., 

 the conjunctiva). There is always redness of the 

 fornix conjunctiva, and usually of the palpebral ditto. 

 There is a muco-purulent discharge, more or less 

 profuse, dependent on degree. The iris is clear and 

 bright, the pupil reacting readily to light, and th& 

 cornea is clear and transparent. In Iritis, the injec- 

 tion is deep-seated, surrounding the cornea as a rosy 

 zone. This is not accompanied by redness of the 

 fornix, or palpebral conjunctiva. The injected ves- 

 sels are beneath the conjunctiva, and do not move 

 with it. The iris is discolored, the pupil sluggish 

 and inactive, and vision is impaired. There is usually 

 very severe pain in the eye and head, generally worse 

 at night. In Trachoma, the upper lid, and particu- 

 larly the free bordex of the tarsus, is affected; 

 the granule is oval, grayish-red, and opaque. It is 

 imbedded in the membrane, and is less prominent than 

 the follicles. They may be found on the ocular con- 

 junctiva, and even the cornea. ' In the granular variety, 

 the affection usually takes on the mixed form, present- 

 ing follicular and papillary hypertrophy in addition to 



