on the Composition of Urinary Concretions . 17 
At length, viz. in 177 6, the experiments of the wonderful 
Scheele were published in Sweden, but were scarcely known 
in this country till 1785. These experiments exploded the 
opinion of the earthy nature of calculi, and substituted that of 
their consisting of a peculiar acid, resembling the succinic, 
and of a gelatinous matter, without any earth. Afterwards 
about of their weight of lime was found by Bergman ; 
which, for a cause now well known, had eluded the acuteness 
of Scheele. Although the experiments of Scheele were con- 
fessedly unquestionable, and were ably supported by the learned 
Bergman, some very eminent chemists, having obtained dif- 
ferent results by their own experiments, adopted a different 
opinion of the composition of these concretions. The im- 
mortal, and ever to be deplored, Lavoisier supposed these sub- 
stances to consist of acidulous phosphate of lime and animal 
matter, many of them being partially fusible ; but still it was 
the unrivalled Scheele who discovered, that the urine of healthy 
persons contains superphosphate, or acidulous phosphate, of 
lime ; and who also indicated the experiment which verified 
his opinion, that phosphate of lime is the basis of bone. 
Experiments have been likewise made, for the most part in a 
rather desultory way, and most of them by persons but little 
practiced in chemical inquiries, which at least afford evidence, 
that urinary concretions are very different, with respect to the 
proportion of the ingredients in their composition, and per- 
haps also in kind. M. Fourcroy, who however must not 
be classed with inexperienced chemists, I believe first obtained 
prussic acid by fire, and by nitric acid, from these concretions ; 
and showed that they sometimes contain phosphate of ammo- 
niac and of soda; which may be dissolved out of them by 
MDCCX.C VIII. D 
