Proceedings of the Royal Institution, 393 



Tlie simplest form of apparatus, and that which is found most 

 useful for the destruction of small calculi, consists of a straight 

 canula, containing within it a thrfee-branched forceps, the elasticity 

 of which causes its tentacles to expand when pushed beyond the end 

 of the canula by which they are concealed ; or rather, when the 

 ttmiila is withdrawn, so as to permit their development. The 

 ends of the forceps are curved, and all of different lengths, so that 

 they cannot include any fold of the bladder, even were it to contract 

 ot^'Tall upon them : they are all united at their manual extreme, 

 forming, by their conjunction, a tube, through which a drill [the 

 length of which is regulated by the length of the forceps, so that it 

 cannot injure the bladder, and the crown of which may be either ex- 

 centric or not, according to the size of the calculus] acts, and grinds 

 away the stone : if the stone be small, it may at once be crushed 

 by the pressure of the drill when held firmly by the forceps ; or, 

 when bored through once, it need not be let entirely to slip from the 

 forceps, in order to make another perforation ; for if the manual end 

 of the instrument be tapped while the branches are slightly relaxed, 

 a fresh surface will be presented, which may be ascertained by the 

 resistance afforded to the drill. At the side of the canula is a fora- 

 men, with a screw or plug, by loosening which the fluid may be 

 allowed to escape. 



-^'.' For the destruction of stones exceeding eight lines in diameter, 

 this instrument is tedious ; and, when repeated sittings are required, 

 it might so happen that one branch of the forceps might enter a per- 

 'fonttion in the stone, and occasion much difficulty in the operation, 

 if not danger to the patient. For the destruction of stones from 

 eight to fourteen lines in diameter, the crown of the drill has been 

 enlarged, so that they may be reduced at once to fragments ; and 

 this has been done in various modes, the most efficient of which 

 would seem to be the projection of a small branch, somewhat re- 

 sembling a comma, from the side of the crown of the drill, after a 

 perforation has here begun, so that it is rendered still more excentric 

 'in its action than the mere excentric drill : this projecting branch or 

 domma can be protruded or withdrawn at pleasure, by a rod which 

 tans through the centre of the drill. The forceps and drill, thus 

 modified, have been named, " Instrument k frois branches et h vir- 



