46 Dr. Pearson's Experiments and Observations , &c. 
<i 
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, which were found to consist of phosphate of 
ammoniac, phosphate of lime, and animal matter, without eon- 
taining uric oxide. 
The difference in the constitution of urinary concretions may 
depend on the difference of the urinary organs of different ani- 
mals, on the food and drink,* and on the various diseased and 
healthy states of the urinary organs. 
I have not found the uric oxide in the urinary concretions of 
any phytivorous animal ; but, whether it would be formed in 
the human animal when nourished merely by vegetable matter, 
must be determined by future observations. In the mean time, 
it is warrantable to conclude, from analogy, that it would not, 
and the application of this fact to practice is obvious ; but I 
now purposely avoid making any practical inferences, until I 
can, at the same time, state a number of facts I have collected, 
relative both to concretions and to the urine itself. 
* I found the stomach-concretion called Oriental Bezoar, to consist merely of ve- 
getable matter ; as did the intestinal concretion of a sheep. 
