VOL. LXXXVIII.] PHILOSOPHICAL TRANSACTIONS. . lQ§ 



lime, after burning away the animal matter and ammonia. As these, and some 

 other experiments, seemed to concur in establishing an important truth, I thought 

 it necessary to examine a urinary concretion of a horse, which, from its figure and 

 size, was unquestionably from the kidney of that animal ; for I have found by ex- 

 perience, that one cannot depend entirely on the accounts in cabinets, nor indeed 

 sometimes on the assertions of persons who collect specimens. 



1. This concretion, which Dr. Baillie was so good as to give me, was of a 

 blackish colour, was very brittle and hard, and had no smell or taste. It felt 

 heavier than human urinary calculi. 2. Under the blow-pipe it became quite 

 black, and emitted the smell, weakly, of common animal matter. It was reduced 

 very little in quantity, and showed no appearances of fusibility, after being exposed 

 for a considerable time to the most intense fire of the blow-pipe. 3. Muriatic acid 

 dissolved this concretion, with effervescence, yielding a clear solution; which, on 

 evaporation to dryness, left a black and bitter residue. 4. A little of the residue 

 (3) being boiled in pure water, to the filtrated liquor superoxalate of pot- ash was 

 added; which occasioned a very turbid appearance, and copious white precipitation. 

 5. Nitric acid also readily dissolved this concretion, with effervescence. The solu- 

 tion being evaporated, partly to dryness, and partly to the consistence of an extract, 

 the dry residuary matter was white and bitterish, and the extract-like part showed 

 no signs of fusibility under the intensest fire of the blow-pipe. 6. A little of the 

 concretion, being triturated with lye of caustic soda, emitted no smell of ammonia. 



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 cal- 

 culus of a horse, in Mr. Heaviside's collection, appeared, on examination, to con- 

 sist of carbonate of lime and common animal matter. Another specimen however 

 of renal calculus of a horse, in the same collection, marked N° 3, was found to 

 consist of phosphate of lime, phosphate of ammonia, and common animal matter. 

 It was fused under the blow-pipe. The specimen marked N° 8, in the same col- 

 lection, which was said to be a vesical calculus of a horse, appeared to consist of 

 the 3 ingredients just mentioned. 



I have met with 2 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 1 specimen, 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 lb. 

 Its composition was principally carbonate of lime and common animal matter*. I 

 have not found any instance of human urinary calculi of a similar composition to 

 that of the rabbit, and those of horses above described, which consist of carbonate 

 of lime and animal matter; and I believe that human urinary calculi very rarely 

 occur of a similar composition to those of the dog and horses above-mentioned, 



* 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 appears probable, that such deposits frequently 

 take place, though I believe they have not been noticed before. — Orig. 



