46 Extraé of Fourcroy and Vauguelin’s 
farther than any before undertaken, have been attended with 
no other fuccefs than to enable us to compare the pheno- 
mena they exhibited with thofe of evaporation. Thus the 
tranfparency of turbid urine, and the concrete flakes preci- 
pitated during the evaporation of urine, have fhewn us that 
the cauftic alkalies, and the precipitate formed by the tanning 
principle in the liquid, belonged to the phofphat of lime and 
a gelatinous animal matter. We have learned, by the fame 
comparative procefs, that even a very gentle heat formed in 
urine ammonia, which fpeedily neutralifed its acidity: that 
its colour embrowned by evaporation, and its abundant cry{+ 
tallifation, on cooling, after it had*been brought to the con- 
fiftence of fyrup, depended on the concentration of the par- 
ticular matter, the common fource of its colour, odour, fa- 
your, and its other characteriftic properties: that the fetid 
garlic fmell, and the cryftalline form, were two of its moft 
prominent characters: and, in the laft place, that. as all 
urine evaporated in this manner forms itfelf into a mats, 
there ought to be found in this mafs the conftituent matters 
of urine, except the portion of ammonia formed and vola- 
tilifed by the evaporating heat. ‘This lamellated eryftalline 
mafs, treated with alcohol, was almoft entirely diffolved, and’ 
nothing remained but a little of the grey faline fubftance 
which the water feparated from the’ phofphat of foda and 
ammonia, and a little phofphat of lime and uric acid, info- 
luble in the liquid, but which was infulated from the calea- 
reous phofphat by the ley of cauftic alkali. Thefe falts, and 
this acid, made fome milliemes only of the weight of the , 
nrine; while the matter diffolved by the alcohol formed 
fome centiemes. The latter was compofed of a little muriat 
of ammonia, benzoic acid, and urinary matter more abun+ 
dant than all the reft, Such is the feries of our analytical 
procefles, analogous to thofe employed on the refidues of 
mineral waters, and by the help of which we have been 
able to feparate the conftituent matters of human urine more 
exactly than had been done before, 
VII. The diftillation of urine, though confidered as well 
known, prefented to us feveral remarkable facts. Ina very 
genile fand-bath, frefh urine giyes water yery ammoniacal 
and 
ince aa a eat ace oaieaet 
—_—w 
= 
ed 
See eee a 
