430 Veterinary Medicine. 



holds to favor this, since the new cells having little vitality are 

 especially subject to granular and other deposits and degenera- 

 tions, with loss of water or of transparency. 



Symptoms and diagnosis. The examiner should apprehend 

 cataract after internal ophthalmia. Much more so, if there is 

 apparent diminution of the bulb, an opalescent zone around the 

 outer border of the cornea, or a marked angle in the curvature of 

 the upper eyelid, as usually occurs in recurrent ophthalmia. 

 When a horse suddenly acquires a habit of shying, of starting 

 back or to one side when approached, when confronted with 

 strange or unexpected objects, or with deep shadows like those 

 from electric lights, he is to be suspected. When he carries his 

 ears in an unusually alert manner, turning one forward and the 

 other back, when he steps higher than before to avoid unseen 

 objects, suspicion should attach to him. If he sees better in 

 twilight than in the full sunlight, central cataract may be feared, 

 while the periphery which is exposed by the dilatation of the 

 pupil in semi-darkness is still clear. In all examinations for 

 soundness, the greatest care should be taken to exclude the pos- 

 sibility of overlooking an existing cataract. 



In the very early stages, while internal inflammation and pho- 

 tophobia are .still present, the pupil may be contracted so that 

 lesion can easily escape notice. Any contraction of the pupil 

 therefore disproportionately to the light, should demand a care- 

 ful examination with the pupil dilated in darkness or by the 

 action of atropia or homatropin. In the more advanced cases 

 with no persistent inflammation and an advanced opacity of the 

 lens, sensitiveness to light is greatly lessened, the pupil is dilated 

 and the cataract is easily detected. 



In cases approximating to the condition last named it is 

 usually only necessary to place the animal in a .sombre or dark 

 building, with his head facing the light at an open door, or 

 window and best with full sunlight. Let this fall full upon 

 the eye, and let the observer view the pupil diagonally from 

 each side when any opacity may be detected. 



When the pupil is too narrow, several drops of a one per cent, 

 .solution of atropia sulphate may be dropped within the lower 

 lid and left for ten minutes until the pupil is widely dilated. 

 Then the examination may be made as above, or still better 



