DISEASES OF THE EYE. 407 



eye will be found to have become more disorganised, until at last cataract, 

 adhesion of the iris, or other disorganisation ensues, and the disease is 

 then at an end. 



After the second attack there will be more or less haziness of the 

 cornea, the iris will have lost its bright colour, .and the pupil will be con- 

 tracted. The corpora nigra will be more pendulous, and will not show 

 the usual jetty blackness ; or they may exhibit slight specks of opacity. 

 After further attacks, the cornea will become so opaque that all within 

 will appear cloudy and confused, except when the lymph clears away to 

 a certain degree at eagh periodical intermission of the attack. We may 

 then find the iris changed into a dark-looking substance, and the struc- 

 tures visible through the pupil may have assumed a glassy green colour, 

 or cataract may have commenced. The lids will become corrugated, and 

 the eye generally will have a sunken " three-cornered look." 



The disease generally affects each eye alternately; but occasionally, 

 when the primary attack is very virulent, cataract forms at once in the 

 eye affected and the disease then ceases, while the other eye remains 

 sound. Usually only one eye is affected at a time. It is very rare that 

 both eyes are attacked simultaneously. 



Specific ophthalmia usually ends in cataract. As soon-as that process 

 is well established, the inflammation generally leaves the eye and does 

 not return. The force of the disease appears to have expended itself, but 

 the formation of cataract nevertheless goes on. Occasionally the disease 

 terminates even more destructively. The crystalline lens may escape 

 from its capsule, and full forward and become attached to the cornea. 

 Sometimes the margin of the iris is torn, and the iris may then hang 

 ragged or may become adherent to the neighbouring structures. 



During the attacks the usual symptoms of fever as indicated by the 

 pulse, by dryness of the mouth, and by constipation of the bowels and 

 scantiness of urine, are present ; but the appetite singularly enough is 

 seldom affected. 



The period of intermission between the first and second attacks varies 

 from three weeks to three months or longer ; but succeeding attacks often 

 follow more rapidly, until the sight is destroyed. 



Though after the first attack the eye may recover so completely that 

 an ordinary person would not notice anything wrong, yet an experienced 

 observer can always detect some trace, such as an unusual degree of pen- 

 dulosity of the upper eyelid, a somewhat prominent haw, a little contrac- 

 tion of the pupil, a slight appearance of gloom and sunkenness about the 

 globe, and an increase of the depth of the white margin encircling the 

 cornea, with, loss of pellucidity immediately round it. The animal is also 

 shy about the head and suspicious of all around, especially on the side of 

 the diseased eye. Each succeeding attack leaves increased traces of 

 mischief. 



As soon as cataract has fully formed, the pupil, instead of being con- 

 tracted as heretofore, becomes dilated, because tile eye is less sensitive or 

 in severe cases wholly insensitive to light. The nature of cataract will 

 be treated of hereafter. 



