Account of a Calculus voided by a Female. 27 



the c^'linder lamps have been tried in two of the most dangerous 

 mines near Newcastle, with perfect success ; and from the com- 

 inunications I have had from the collieries, there is every rea- 

 son to believe that they will be immediately adopted in all tiie 

 mines in that neighbourhood, where there is any danger from 

 fire-damp. 



VIII. Account of a Calculus voided by a Female. 



To Mr. Tilloch. 



Sir, — Xi. FKW weeks since I was requested by a respectable 

 surgeon to examine a fragment of calculus voided by a female 

 patient of his. The fragment weighed about three grains and 

 a half, had somewhat of a rhomboidai figure ; was evidently con- 

 vex on the one side, and concave on the other. The convex 

 surface was considerably nodulated, but the concave was smooth. 

 When viewed with a magnifier, it showed distinct marks of strati- 

 fication of alternate layers of a grayish and dirty yellow coloured 

 substance. On being heated to redness before the blowpipe it 

 lost nearly *o of its weight; that is, after it had been kept in the 

 heat of boiling water for some time: by uiging the heat still 

 further it fell to powder, lost its former colour, and gained a 

 slight tinge of red, losing more than •! more of its v,eight. 



I wa? then induced to trv tl;c effect of acids on this substance, 

 and accordingly took a portion of it which had been treated 

 as abo\-o, and found it to dissolve in muriatic acid without ef- 

 fervciccnce, leaving but the smallest possible quantity, which I 

 conceived to be animal matter. I then took a portion of the 

 substance as it was voided, which dissolved also in muriatic acid, 

 but with considerable effervescence. I was at first unwilling to 

 attribute the effervescence to carbonic acid ; but upon examiiia- 

 tiou by lotting up lime-water into tlie gas in a test tube standing 

 over mercury, I was convinced of its being the case. The solu- 

 tions v.eie next examined, and were found to contain lime, plios- 

 phoric acid, and iron. Therefore the calculus is composed of 

 carbonate and phosphate of lime, and oxide of iron, with a verv 

 miinite portion of animal matter; for when the residuum, which 

 vv-as found to be insoluble in muriatic acid, was separated and 

 heated to redness on a slip of platina, it exhibited distinctly the 

 peculiar smell of burnt feathers or other animal substances*. 



I am not exactly aware, whether the carbonate of lime has 



* IVoin tlic figure of tlic friifiinent, as vvcll as that wliicli I have .-iiii-t^ 

 received, ii li;iR cviflctitly hccii detached from a nucleus apparently of 

 ^-4ihb ol'un inch ill diuiuetci'. 



hithortu 



