446 So)ne Remarks on Urinari/ Calculi, 



what else could it be but ammonia in this case, even if the odour 

 had not proclaimed its presence ? and from whence could the 

 ammoniacal gas arise but from the lithate of anmionia ? It is 

 not conceivable that it could be obtained by the simple action 

 of the potassa on any mucus supposed to be obtained from the 

 bladder ; or to be the result of a synthetic structure of ele- 

 ments resulting from the lithic acid itself, part being decom- 

 posed by the action of the potassa, and new modelled in this 

 form. As far as we know, neither can be the source of the am- 

 monia thus presented. 



Though Professor Berzelius had stated his having met with 

 silica in the urine, Dr. Prout, in his valuable work on calculous 

 diseases, expresses himself completely sceptical as to the exist- 

 ence of silica in calculi. But M. Thenard, in his very excellent 

 *' Traite de Clumie" even describes the characters of siliceous 

 calculi. He mentions that they possess the same aspect as 

 those composed of oxalate of lime, perhaps a little less colour- 

 ed ; and that they lose nothing by calcination, and form glass 

 by fusion with potassa. 



I had occasion not long since to examine fragments of a cal- 

 culus passed by a gentleman labouring under this dreadful 

 disease. It had all the geiieral chai'acteristics of the ammo- 

 niaco-magnesian phosphate or triple calculus. It was "isliite, 

 crystalline^ and disengaged ammonia by treatment with caustic 

 potassa, in which it was soluble ; nor was it entirely soluble in 

 sulphuric acid. The insoluble residue had all the characters of 

 silica, and fused into glass with potassa. The calculus in ques- 

 tion, though almost transparent, like that composed of ammo- 

 niaco-magnesian phosphate, was not vitrijiahle at a red heat. 



The gentleman in question found considerable pain in pass- 

 ing his urine ; unless his conmion food was composed of bland 

 substances, as barley broth, &c. 



His medical attendant was very judiciously administering 

 muriatic acid. But unless this was conjoined with such bland 

 vehicles, the sensation was described to me as that which might 

 be supposed to arise from an excoriation of the membranous 

 surface by powdered glass. 



The method I adopt in order to obtain a general idea of the 

 constituents of uruiaiy calculi being sufficiently simple, perhaps 

 a succinct detail of it may not be uninteresting to the medical 

 practitioner; seemg the manipulation is so easy, and the che- 

 mical skill required so very small. 



The cystic oxide and the zanthic oxide calculi are so very 

 rare in occurrence, that for the general practitioner they might 

 be well passed unheeded ; confused crystals and its feet id odour 

 before the blo^v-pipe characterize the first of these ; and the last 



is 



