( 147 ) 



and that the volatile fait in it (for of thefe two falts the Stone in 

 the Bladder does for the moll part confill) when expofed to the 

 moill air, will not diflblve : that in the volatile fait there are par- 

 ticles fo fixed that they cannot be dilfolved but by the force of fire ; 

 I cannot, lor my part, perceive that any medicine can be found of 

 fufficient efficacy to diflblve or break in pieces the Stone in the 

 Bladder. And when we reflect on the lliarp-pointed particles of 

 the volatile and fixed falts which, for the greateft part, compofe 

 the Stone in the Bladder, we are not to wonder that thole Stones 

 excite fo much pain ; efpecially, if we confider the Iharpnefs of fo 

 many wonderfully minute faline particles, and the many nerves in 

 the Bladder, (for with any frefli accretion of matter new faline par- 

 ticles are added) which, with their Iharp points pierce and irritate 

 the infide of the Bladder. 



I broke one of thefe Stones into fmall pieces, and examined them 

 by the micro fcope, when I found that thefe Stones confill of fuch 

 irregular parts as if we beheld a fubltance compounded of a great 

 quantity of grains of land. And in thefe obfervations I often per- 

 ceived thole wonderfully minute particles which I deemed to be falts, 

 and which I have faid confill of volatile fait, and which appear to 

 be of the fame nature with the calcareous fubfiance in the limbs of 

 gouty perfons. I have caufed a drawing to be made of a very 

 fmall particle, broken off from the interior part of one of thefe 

 Stones, partly to fhew the formation of the Stone, and partly to 

 exhibit the ^vonderfully minute and fliarp-pointed faline particles, 

 but which I feldom faw in fo great a number as are here Ihevvn ; 

 the reafon of which I take to be, that the particles of which the 

 Stone confifts adhere together fo very clofely. 



Fig. 26, A B C D E F G H, is this fmall particle of Stone, which 

 to the naked eye appeared the fize of Jig. 27. B C D E F, repre- 

 fent the very minute faline particles which are only to be dillin- 

 guilhed at the edges of this fragment. The Stone from which this 

 piece was taken, together with feven or eight others, had been 



T 2 



