244 Experimenis on Urine. 
The corrofive muriat of mercury is a very ufeful re-agent, 
as it has no immediate effect upon recent healthy urine; but. 
in every cafe of increafed aétion of yeflels, more particularly 
of the inflammable kind, a greater or lefs milkinefs, and a 
whitifh precipitate, is inftantly produced; it hkewife in fome 
degree coagulates dropfical urinc.—Effects fomewhat fimi- 
lar, although not fo firiking, are produced by alum, 
The muriat of barytes detets the phofphoric falts. Four 
oz. of healthy urine yield with this. re-agent a precipitate. 
of 13 gr. equivalent to about 24 or 25 gr. of microcofmic 
falt, confifting of fuch a mixture of the phofphats of foda 
and ammonia as are ufually met with in the urine. This 
fabftance will therefore fhew when thefe falts are deficient, | 
or in too great a quantity. The fulphat of iron has.a fimilar 
effect, but is not fo certain, as any little excefs of acid might 
prevent the feparation of the phofphat of iron. 
The nitrats of mercury and filver are decompofed by the 
phofphoric and muriatic falts, and hkewife, in fome degree, 
by the extractive matter; they can, therefore, be but of 
tittle ufe as re-agents. 
The acetite of lead is decompofed by the muriatic and 
phofphoric falts : with the laft it forms an infoluble preci- 
pitate; but the muriat of lead may be diflolved by 18 or. 
20 times its weight of hot water. This circumftance affords 
a ready method of determining their relative proportions ; 
for, if we precipitate a given quantity of urine by this fub- 
fiance, dry the precipitate, and then digeft it in 20 times its 
weight of diftilled water, what remains muft be phofphat of 
lead, and the quantity taken up will indicate the proportion 
of muriat oflead. Four oz. of healthy urine treated in this 
way yield a precipitate of 31 gn: ; this being digefted in dif-. 
tilled water, 7 gr. were taken up, the remaining 24 gr. 
were found to be phofphat of lead, equivalent to 23 or 24 
gr. of microcofmic falt, as was determined direétly by expe- 
riment, 
It 
