[ ^33 ] 



adhere clofely to this membrane in every part, even to the border 

 or edge of the cryftaUine capfula, to which capfula the cataradl 

 has not the fmalleft adherence ; the foffula or bed alone muft 

 give fome degree of ftabihty to the cryftalhne ; but when to this 

 we add its envelope, the covering of the iris, and its ftrong 

 adhefion to the vitreous membrane, we muft be convinced that 

 nature has paid uncommon attention to the fecurity of this 

 body, and that no fmall pains and attention are neceffary to 

 difplace it. Certain it is, that if a fufEcient opening were 

 made in the capfula the cryftalline may be thrown out of it 

 by means of its contained liquor : But are the fmall pointed 

 needles, moflly ufed, \vcll calculated for this purpofe i" they 

 undoubtedly are not ; they perforate this membrane, and flick 

 in the cryftalline, which is of a thickifh vifcous fubftance, often 

 much harder than in its natural ftate. Pains are taken to re- 

 move this opaque body, but the needle does not afford a fufEcient 

 paffage for its exit; the parts are prefTed down, and the vitreous 

 membrane, and of courfe the iris, muft yield to this prefTure, 

 from their connedions with each other, without the aid of any 

 imaginary adherence of the cryftalline or its capfula to the iris : 

 but let us fuppofe the catarad fairly diflodged from its bed by 

 a proper opening of its capfula ; are there no other obftacles to its 

 precipitation ? there are, and confiderable ones ; the vitreous 

 membrane and its adhefion to the iris oppofe it, fo does the 

 denfity of the vitreous humour itfelf. Thefe are now the real 

 difficulties, and none other. It is for thefe reafons that the 

 catarad fometimes flips into the watery chamber of the eye, 

 which from its tenuity gives lefs refiftance to it ; and it is this 



, circumftance 



