¢ 
«of Urinary Concretions. 273 
burning away of the animal matter: hence the refiduary | 
phofphoric acid readily fufes, and, uniting to the phofphate 
of lime, compofes fuperphofphate of lime, a very fufible 
fubftance. 
The phofphate of ammoniac being diffolyed owt by water, 
or cauftic alkaline lye, the remaining matter is infufible, 
being phofphate of lime. 
A very hard, brittle, and blackith inteftinal calculus of 2 
dog, from Mr. Wilfon, was found to be of greater fpecifie 
gravity than human urinary calculi, and to have the fame 
‘compofition as that of the dog above defcribed. 
This alfo was found to be the compofition of a white, 
fmooth, round, inteftinal calculus of a horfe, the fpecific 
gravity of which was 1,791. 
The fame compofition was difcovered, on sienna a 
yery hard, gray, brittle, laminated, quadrilateral concretion, 
faid to be from the urinary bladder, but which, I think, was 
more probably from the inteftines, of a horfe. 
‘ II. On a Calculus from the Urinary Bladder of a Rabbit, 
This is alfo a curiofity, being the only inftance I have 
feen. I am likewife indebted to Mr. Thomas for this 
fpecimen, which he very kindly fent me, fitted up as a 
preparation, included in the bladder itfelf. Mr. Thomas 
found this concretion, on diffecting a perfeGly healthy and 
very fat rabbit. 
This fpeeimen is fpherical, and of the fize of a {mall nut- 
meg. It is of a dark brown colour, has a {mooth furface, is 
hard, brittle, and heavy. When broken, it appeared to 
confift of concentric lamine. Its {pecific gravity was 2. 
1. Under the blowpipe it grew black, and emitted, the 
fmell of animal matter while burning; at laft it ceafed te 
emit any fmell; and, urged with the intenfeft fire, flowed 
no figns of fufibility, 
2. It readily diffolved, with effervefcence, like marble, in 
both muriatic and nitric acids, giving clear folutions. 
3. The 
