CATARACT. 123 



terprizes. The forcible retraction of the eyeball into the orbit 

 the instant any instrument touches it, together with the simultane- 

 ous protrusion of the haw, will be found plaguy annoyances; and 

 though instruments have been contrived to counteract these hin- 

 drances, yet is their employment apt to create a good deal of irri- 

 tation and inflammation, and thus, after all, foil us in our best in- 

 tentions. And not only at the time of, but even after, the opera- 

 tion, has the retraction of the eyeball been followed by prolapse of 

 the iris ; or, worse still, bursting of the globe and escape of the 

 vitreous humour. 



For the Operation to prove successful, other parts of 

 the eye immediately concerned in vision will require to be in a 

 sound or normal condition. Should the cataract have been the 

 product of successive attacks of periodic ophthalmia, such can 

 hardly be expected to be the case ; and, therefore, it would be 

 fruitless to operate. In fact, the only case, strictly speaking, suit- 

 able for operation, is that wherein the cataract is of that descrip- 

 tion that has arisen spontaneously, or, at all events, with so little 

 concomitant disturbance that it is not likely other important parts 

 of the eye have become anywise disorganized ; for, unless their 

 impairment could be rectified, it is evident that all the good result- 

 ing from the operation must be nullified. Surgeons, I believe, in 

 general, refuse to operate for cataract, unless the patient can, by 

 certain sensations, distinguish light from darkness : perhaps this 

 test, with horses, would be somewhat difficult to arrive at. But, 

 we will suppose that the eyes are in a condition for an operation ; 

 and, further, that the operation has turned out, so far as the re- 

 moval of the opaque lens is concerned, successful; even then it does 

 not follow that the animal is to regain his eyesight, or enough of 

 vision even, to be of any service to him. The eye, having lost its 

 principal refractor and regulator — the crystalline lens — will require 

 some artificial substitute. Eye-glasses supply this deficiency in 

 man; but, as has been before asked, could a horse be fitted, or 

 have his eyes suited, with any sort of glasses ] And were this 

 possible, still, would his restored vision be of a character to render 

 him really safe and serviceable to us? or would it be of that im- 

 perfect kind, converting him from a steady, sure-footed, trust- 



