Professor Dana on Morbid Animal Products. 149 
Ant. XIII.—Chemical Examination of some Morbid Ani- 
mal Products : by James Freeman Dana, M.D. Pro- 
fessor = Chemistry, &c. in Dartmouth College. 
In the. spring of 1820 I had an opportunity of analysing 
a extensive collection of Urinary and other calculi belong- 
to the Anatomical Museum of Harvard College ; this 
co atsetion was presented to the College by the late Dr. 
Nicxots of London, and for the privilege of examining it, 
I am indebted to the ‘politeness ees the ne of Anatomy 
in that College, Dr. J. C. Warren, of Bosto 
The examination of these Caleuli was pesihserend with a 
view to ascertain the relative numbers of the different spe- 
cies in this collection, but it became very interesting in its 
progress, as I found calculi which contained Urate of Am- 
by Fourcroy and Vauquelin, but as this substance was not 
detected in the extensive examinations of calculi by Dr. 
Wo.taston, or by Mr. Branpe, it is well known that its 
existence as a component part of urinary concretions has 
been questioned, and it has been supposed that the French 
chemists were deceived by fi ious appearances. From 
the experiment of the British -cheitiniats,it it cannot be inferred 
that urate of ammonia never EE Ae EY but that it is of 
very rare occurrence ; I am peculiarly fortunate in having 
had an opportunity to examine some calculi of which it isa 
ee part. : 
e existence of ammonia in calculi is acknowledged by 
Mr. Branpe, and his experiments lead him to conclude 
that it was combined with muriatic acid ; I have not yet had 
an opportunity of seeing a detailed account of his experi- 
ments, but his great and deserved reputation as a chemist, 
has led me in common with others, to place great confidence 
in his results. Wika; crerefore, I first detected ammonia in 
these calculi, no doubt was entertained that it was combin- 
ed with muriatic acid, and accordingly the appropriate tests 
for that substance were applied, but the appearances pre- 
sented were so different from those produc ced by muriatic 
acid, that I was led to a further examination, and found the 
acid to be urve. 
