PERIODIC OPHTHALMIA. 557 



The subsidence of the attack is marked by a diminution of 

 the inflammatory symptoms, the haziness slowly disappears from 

 the cornea, the pupil becomes larger, less contracted, rounder, 

 disclosing the lens altered to a hazy grey colour, the result of 

 change in its substance, or a deposit on its surface, the prelude 

 to cataract ; the pupil in many instances does not regain its 

 former dimensions, even after a first attack, the iris having 

 become fixed by adhesion ; the cornea may regain its natural 

 hue, but the iris is more or less permanently altered in aspect 

 and colour, and the eye seems smaller than natural: this is 

 caused by its continuing in an irritable condition, and its 

 being drawn backwards by the retractor muscle, even after the 

 apparent subsidence of the disease. As time advances, the 

 opacity of the various structures becomes less apparent; but 

 sometimes the cornea is clouded by an interlaminal deposit, and 

 generally the eyebrow remains in a peculiarly wrinkled condi- 

 tion. This wrinkled appearance of the eyebrow after the acute 

 symptoms have passed off, is characteristic of periodic ophthalmia. 

 The eye, having regained more or less of its natural appearance, 

 may remain free from active disease for an indefinite period. 

 In some instances the disappearance of the acute symptoms may 

 go on satisfactorily for three or four days, when, without any 

 appreciable cause, the eye is again found highly inflamed, the 

 eyelids closed, and the animal seemingly suffering intense pain ; 

 whilst in other instances the active signs of the disease totally 

 disappear for several weeks or months, and then recur again and 

 again, until cataract is fully developed ; other cases are marked 

 by complete subsidence of the disease in one eye, and its appear- 

 ance in the other; its mode of procedure in such cases is to 

 attack one eye, then the other, until both are permanently 

 altered in structure, and the animal is left totally blind. 



Ordinarily, bhndness and complete disorganization are fol- 

 lowed by a cessation of the paroxysms ; but there are exceptions 

 to tliis, and I have met with cases where acute inflammation 

 has recurred periodically for years after a cataract has been fully 

 developed. 



It is quite possible that one attack may disorganize the organ 

 to such an extent as to cause it to assume the appearance of a 

 bulbous mass, the iris driven into the aqueous chamlier, adherent 

 to the cornea; the lens dislocated; and all the structures, 



