on the Composition of Urinary Concretions . 45 
matter was white and bitterish, and the extract-like part 
showed no signs of fusibility under the intensest fire of the 
blowpipe. 
6. A little of the concretion, being triturated with lye of 
caustic soda, emitted no smell of ammoniac. 
From these experiments it appears, that this calculus, like 
the former one from a rabbit, consists of carbonate of lime and 
common animal matter. 
A renal calculus of a horse, in Mr. Heaviside’s collection, 
appeared, on examination, to consist of carbonate of lime and 
common animal matter. 
Another specimen, however, of renal calculus of a horse, in 
the same collection, marked No. 3. was found to consist of phos- 
phate of lime, phosphate of ammoniac, and common animal 
matter. It was fused under the blowpipe. 
The specimen marked No. 8. in the same collection, which 
was said to be a vesical calculus of a horse, appeared to consist 
of the three ingredients just mentioned. 
I have met with two instances of a deposit of a prodigious 
quantity of matter in the urinary bladder of horses, which had 
not crystallized, or even concreted : it amounted, in one speci- 
men, which was given to me by Dr. Marshall, to several 
pounds weight; and in the other, which is in the possession of 
Mr. Home, to about 45 pounds. Its composition was, princi- 
pally, carbonate of lime and common animal matter. * 
I have not found any instance of human urinary calculi of a 
* Since this paper was read, Mr. Blizard has been so attentive as to send me 
another specimen of the same kind of deposit as those here mentioned. It now ap« 
pears probable, that such deposits frequently take place, although I believe they have 
not been noticed before. 
