O F T H E E Y E S. 379 



comprefTun upon the optic nerve, very little 

 can be done with an expedation of fuccefsj 

 and much lefs if it arifes from a palfy of that 

 or any neigh bearing part. 



A cataraB, like many other difeafes, is 

 attributed by different practitioners to dif- 

 frrent caufcs, though the greater part coin- 

 cide in opinion that the defect is in the cryf- 

 talline humour of the eve, which, becoming 

 opaque, prevents the admiiiion of thofe rays 

 upon the retina that conftltute vifion. To 

 enter at large into the profeffional definition 

 of thefe diftindl difeafes, and mod minutely 

 into the probable or poffible means of relief, 

 would be to extend this fubjeCt beyond the 

 limits or compafs of the v;ork itfelf. I fhall 

 therefore reconcile to myfelf the communi- 

 cation of a fact almoft univerfally acknow- 

 ledged — that little even in the human fpecies 

 is now expedted from the famous operation 

 of couching; an experiment that is, taking 

 it *' all in all," productive of advantages fo 

 very trifling, the recommendation of it here 

 can avail but little, particularly as the expenfes 

 added to the hazard and uncertainty of cure 

 7 ' could 



