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trary to expectation, a large quantity of this humour 
^ pei haps a third part, or more) has been fometimes 
difcharged, without any bad confequence. 
I have fuppofed, that the great and foie benefit 
arifing from this improvement, is the eafy repara- 
tion of the cryftalline from the bed of the vitre- 
ous humour, fo that none of the vitreous humour 
fhall be evacuated. But perhaps it will alfo be ap- 
proved of, as it will render unneceffary the meafure 
prefcribed by Monf. Daviel, of wounding the mem- 
brane of the cryftalline, before we proceed to the 
extraction of the cryftalline itfelf: To which pur- 
pose he advifes the flap of the cornea to be fufpended 
with a fmall fpatula ; then, with a pointed cutting 
needle, to wound the furface of the cryftalline; 
after which, to introduce the fame fpatula through 
the pupil, in order to detach the catarad from the 
iris, and then proceed to the expulfion. 
I have here recited thefe proceftes of M. David’s 
operation, which are calculated merely to procure an 
eafy operation of the cryftalline from the vitreous 
humour : But they are difficult to the operator, fa- 
tiguing to the patient, and, I ffiould hope, altoge- 
ther needlefs, if the knife be ufed in the manner 
which I have recommended : For, whether the cap- 
fula of the cryftalline be nothing more than the du- 
plicature of the membrane of the vitreous humour, 
or whether it be a proper coat, which is alfo cover’d 
by the membrane of the vitreous humour ; in either 
cafe, ftnce by compreffion the chryftalline advances 
with fo much facility through the* pupil, it will be 
eaffiy feized by the knife, and removed from the 
vitreous humour, with its inveloping membrane : 
T t Whereas, 
