

Siliceous Deposits from the Urine. 259 



to the action of a stream of carbonic acid gas, from a capillary 

 jet, it became turbid, and a white powder subsided, soluble with 

 effervescence in diluted hydrochloric acid, and which was again 

 precipitated by oxalate of ammonia. Hence there can be no 

 doubt that the base of this particle was lime. 



Another fragment of the same external characters being 

 placed on a capsule, was dissolved with considerable efferves- 

 cence by a few drops of diluted hydrochloric acid. The whole, 

 however, was not entirely dissolved, but there remained at the 

 bottom of the capsule three very minute crystals, which the 

 acid could not dissolve, though aided by heat. The muriatic 

 solution was very carefully withdrawn, and on being neutralized 

 and heated with oxalate of ammonia, oxalate of lime precipi- 

 tated. The three crystals were now carefully washed and 

 removed to a platinum capsule, and boiled with concentrated 

 nitric acid, but without undergoing the slightest perceptible 

 change. The acid was driven off by evaporation, and the crys- 

 tals submitted to the action of the blow-pipe on the platinum 

 capsule, but without suffering any alteration. A little potassa 

 and soda being added, on urging with the blow-pipe flame, 

 solution with effervescence was effected, and the whole fused 

 into a perfectly transparent colourless globule. The globule 

 being pulverized and heated with distilled water, hydrochloric 

 acid being added in excess, a gelatinous mass of very small 

 bulk subsided after a considerable interval. When the jelly 

 had consolidated into a closer and much less bulky deposit, 

 which it did after a couple of days, the supernatant fluid was 

 carefully withdrawn, and the precipitate being well washed 

 with hot muriatic acid, was transferred to a small capsule, and 

 the whole evaporated to dryness, leaving behind a white in- 

 soluble powder, which resisted the most intense action of the 

 blow-pipe. 



This analysis, therefore, fully proves that the little fragment, 

 instead of being, as I at first imagined, composed of the fusible 

 phosphates, consisted of carbonate of lime, with a very minute 

 though still sensible proportion of crystallized silex. Hence 

 then it would appear that silex, though rarely, does occa- 

 sionally appear in a crystallized form in the urine. Berzelius, 

 indeed, estimates its quantity at .03 in the thousand parts, but 



