Gn Gravelly and Calculous Concretions. 3oS 



nvice lalteily repeated, and always with the same result 

 (care being taken to keep the temperature, as nearlv as pos- 

 sible, for a few hours, between 90 and 100 degi-ees,) af- 

 forded one of the most pleasing objects imaginable^, A'iz. 

 the formation of this crystalline matter, under all the dis- 

 advantages of elevated temperature and constant agitation, 

 from (I may almost say) their primordial moleculee to the 

 accomplishment of their full size. And here, indeed, they 

 are most beautiful, and not to be distinguished from those 

 spontaneously deposited. 



^ The whole experiment strikes us strongly with a sem- 

 blance of what probably passes, under similar circum- 

 stances, in nature ; and reminds us of the danger attendant 

 upon acid impregnations, more particularly at bed-time, 

 when the urine, by many hours retention and quiet, has 

 ample time to deposit its uric acid contents in the bladder. 

 From it also we learn, that the temperature of the human 

 Dody, in place of retarding or preventing (as might be ex- 

 pected a priori) these pernicious eftects, rather' promotes 

 them, and that to a considerable degree. 



But whilst wc endeavoured to establish this point, from 

 practical observation as well as experiment, we seem to 

 have entirely forgot that the urine itself is an acid liquor, 

 and that therefore, if acids were so prejudicial, it is not pro- 

 bable that the provident wisdom of nature would commit 

 the discharge of this necessary excretion to a fluid, which, 

 by prematurely separating it within the body, would com- 

 pletely defeat the r,bject of her humane attention. And 

 would she not, in the infinity of her resources, dispose of 

 it by some less objectionable emunctory ? 



1 would, in the first place, observe, that though healthy 

 urine manifests the properties of an acid liquor, it is in the 

 very smallest possible degree,- so much so, that though 

 mentioned long since by Moraung, CoJdevillars, and oth°er 

 surgeons, yci it was not, either chemically or medically, 

 acknowledged to be so, until the time of Scheele, who 

 linally cstabli.-hed this point, as well as the nature of the 

 prevailing acid. And, secondly, that nothing can be more 

 erroneous than the opinion, which so long prevailed, that 

 the phosphoric acid existed in it in a naked or uncombined 

 state. It IS now well established that it is only in that of 

 H weak acidule, or acidulous phosphate of lime, very little 

 ^hort, indeed, of the point of saturation; and hence th« 

 wcaknc'3 of its acti(jn as an acid liquor: for were it not for 

 litmus, and some of the more delicate of the vegetable 

 blucti, we should have been, even to this dav, ianorant ot 



thiH 



