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CALCULI. npB 



aiid requires a rery considerable increased proportion of Experiments 

 lime-water to decompose it, for, obvious reasons. This we ^"j^ ^g?^^|j^ ; 

 find always depositing, sometimes from the bladder itself, &o. " - 



but, generally, before it has entirely parted with its natu- 

 ral temperature, a very large proportion of a reddish brick- 

 dust like sediment, (a welcome harbinger to gouty patients.) 

 gradually declining, and keeping pace with the alleviation 

 of symptoms, and the progressive return of the urin.e to its 

 natural degree of acidity. This sediment, Scheelc, Berg- 

 man, and Fourcroy, consider of the uric acid kind: and 

 so it (but in part only) undoubtedly is ; being in a smaller 

 proportion than they were aware of. For, considering that 

 the enormous quantity, rendered in a few days, was in- 

 compatible with the known minute proportion of this acid 

 matter in urine, I was determined to make the following 

 experiment. To a considerable quantity pf it, desiccated 

 and well edulcorated with distilled water, were added three 

 Ounces of a weak alkaline lixivium ; which, after a few hours 

 digestion, completely discoloured it, acquired a golden yel- 

 low colour, a sweetish taste, and, on the addition of a . 

 few drops of dilute marine acid, precipitated a copious 

 sediment of whitish minute needle-shaped crystals^ of a 

 silky appearance. 



To this precipitate, w^ell edulcorated, was added, by de- 

 grees, about one ounce of weak nitrous acid, which acted 

 on it, with effervescence, and nearly took up the whole. 

 This solution, being set to evaporate, began to redden the 

 fingers,, and other animal matters: no doubt, therefore, 

 could subsist, as to its nature. To the remainder, whick 

 seemed very little diminished, and only deprived of co- 

 lour, were added two ounces of dilute marine acid; which^- 

 after some time in digestion, nearly dissolved the whole: 

 and, finding this acid solution precipitate with lime-water, 

 oxalt of ammonia, and fixed alkali, it must have been phos- 

 phat of lime. This forms, then, by far the largest pro- 

 portion of the gouty sediment, which is coloured by the 

 precipitated uric acid. Such, also, is the result of Crook- 

 shank's experiments; and so we should expect to find it, as 

 I shall endeavour to point out, on a future occasion. 



Let us now consider, how far these analytical results 



mav 



