of Practical Surgery. 403 



tisfying our present doubts, it is very possible. An appa- 

 ratus might easily be contrived for the purpose. All that 

 is requisite is, a piece of brass, about four inches long and 

 two inches square, supported by two or more feet, and per- 

 forated longitudinally, lo admit a thick steel pin, which 

 pin is to be fitted to the perforation in the brass, so as to 

 move very freely, and to exceed the brass about two inches 

 or more in length. On the upper end of this pin, I would 

 have a small flat piece of brass fixed, capable of holding 

 weights ; and in the lower end, a hole made, into which the 

 different shaped points on which we are desirous to make 

 experiments are to be fixed, similarly to the shifting feet of 

 common compasses. Immediately below this pin I would 

 place a species of drum, consisting of a small box, with 

 bladder or other elastic substance stretched over it to imitate 

 ihe animal tunics. Now it is evident, that by placing dif- 

 ferent weights on the upper end of the pin, until the point 

 we are experimenting on pierce the stretched bladder, we 

 may be able exactly to appreciate the comparative advantage 

 of the different kinds of point v 



7th. The operation of couching frequently fails, from the 

 cataract or opake crystalline lens being of a soft consistency; 

 which the couching needle, instead of depressing, passes 

 through and divides. If the broad part which is, I believe, 

 frequently used in depression, were made concave so as to 

 fit the convex edge of the lens, might it not in some degree 

 remedy this evil ? 



8th. Considering that the majority of calculi in the blad- 

 der are more or less spherical, it appears to me that the 

 forceps now used in lithotomy is not of the most advan- 

 tageous construction. By each side of the beak of the 

 usual forceps being concave, with an oval hole at the bot- 

 tom of the concavity, similar to the forceps once used in 

 extracting polypi, the edges of which hole A and the sides 

 of the concavity, might have teeth, Would it not be more 

 iikely to lay hold of even an irregularly spherical calculus 

 than the forceps at present used, with toothed beaks and 

 flat sides ? and which seems better contrived for crushing 

 a soft calculus to pieces, than for holding it fast and with- 

 drawing it whole. 



9th. Grown bold by practice, I shall now venture, as my 

 last suggestion, to propose another kind of forceps for ex- 

 tracting the stone. Let us suppose a forceps with the beaks 

 formed of two narrow elliptical rims, jointed so as in some 

 degree, by tjie pressure upon a calculus, to conform them- 

 selves lo its size. To the edges of these rims I would at- 

 2 C 2 taefi 



