O F T H E E Y E S, 379 



compreffion upon the optic nerve, very little 

 can be done with an expectation of fuccefs; 

 and much lefs if it arifes from a palfy of tliat 

 or any neighbouring part. 



A cafaraBy like many other difeafes. Is 

 attributed by different praftitioners to dif- 

 ferent caufes, though the greater part coin- 

 cide in opinion that the defedl is in the cryf- 

 talline humour of the eye, which, becoming 

 opaque, prevents the admillion of thofe rays 

 upon the retina that conftitute vifion. To 

 enter at large into the profeflional definition 

 of thefe diftind: difeafes, and moft minutely 

 into the probable or poflible means of relief^ 

 would be to extend this fubjecft beyond the 

 limits or compafs of the work itfelf. I fhall. 

 therefore reconcile to myfelf the communi- 

 cation of a fad: almoft univerfally acknow- 

 ledged — that little, even in the human fpecies, 

 is now exped:ed from the famous operation 

 of couching -, an experiment that is, taking 

 it " all in all," produd:ive of advantages fo 

 very trifling, the recommendation of it here 

 can avail but little, particularly as the expences 

 gdded to the hazard and uncertainty of cure 



could 



