414 Veterhiary Medicine. 



intervals, but continues to exhibit morbid phenomena which be- 

 tra}' the previous existence of the disease. The recognition of 

 such persisting lesions is all the more easy that one eye only is 

 usually attacked at first and a comparison between this and the 

 sound eye renders the modifications all the more patent. Even 

 after a fir.-^t attack there is usually a hazy bluish white zone 

 round the outer margin of the cornea and this becomes more dis- 

 tinct after each successive attack. The fault)' eye is distinctly 

 smaller in appearance, at first because it is retracted in its sheath 

 and later in certain cases because of actual atrophy. In propor- 

 tion to the retraction of the bulb, is the protrusion of the mem- 

 brana nictitans which covers a greater part of that eye than of its 

 fellow. The upper eyelid in place of forming a continuous and 

 regular arch shows a distinct abrupt bend between its inner and 

 middle thirds caused by the contraction of the levator mu.scle. 

 The front of the iris has lost something of its normal lustre, and 

 the posterior chamber is liable to show an abnormally light re- 

 flection, greenish yellow or yellowish blue. Under direct il- 

 lumination, lines of opacity may be detected in the aqueous 

 humor, or in the lens, or dark filaments in the vitreous. After 

 several attacks the lens is very distinctly obscure and this in- 

 creases with each relapse to a white or yellowish white complete 

 opacity. After the fir.st or second attack the pupil may be dis- 

 tinctly contracted, while later in the disease, with advanced cata- 

 ract it is usually widely dilated. Another feature is the erect, 

 attentive carriage of the ear, to compensate for the waning vision. 

 Lesions. These are not often seen, as animals do not often die 

 of this disease. Beside the superficial lesions of the conjunctiva 

 and cornea which may be seen during life, exudates have been 

 found on the posterior surface of the cornea, in .some cases binding 

 that to the iris. In advanced cases the greatly contracted anterior 

 chamber may contain a little mucilaginous liquid strongly pig- 

 mented with debris from the iris, the whole mixed with shreds of 

 exudation. The iris is thickened by congestion and by exuda- 

 tion on its surface and in its substance, and is displaced forward 

 so as to diminish the size of the anterior chamber, and it may 

 have contracted adhesions with the cornea (anterior synechia) or 

 with the lens (posterior synechia). This leads to unevenness in 

 the pupillary margin, where the iris is often torn into shreds. 



