3 8 ° 
Mr. Hatchett’s Observations 
analyses made on the urine of the same and of different ani- 
mals at various times, and under different circumstances. 
I am, &c„ 
CHARLES HATCHETT. 
P. S. Since the foregoing letter was written, Mr. W. 
Brande has examined the urine of the horse and ass ; the 
result is as follows : 
“ The urine of the horse is turbid, and of a mucilaginous 
consistence ; it changes the colour of vegetable blues to green, 
and when exposed to the air it becomes covered with a thin 
pellicle of carbon at of lime. 
“ When evaporated to the consistence of thick honey, it 
yields to alcohol a small portion of urea. The salts which it 
contains are as follows : 
Carbonat of lime 
— — soda 
Sulphat of soda 
Muriat of soda 
Benzoat of soda 
Phosphat of lime. 
“ These amounted in the present instance to about ofte- 
eighth of the urine. I could discover no trace either of pot- 
ash or ammonia. 
The urine of the ass is somewhat mucilaginous : but at the 
same time transparent. Like that of the horse it changes 
vegetable blues to green ; but it deposits no carbonat of lime. 
“ It differs in its composition from that of the horse, by 
containing a much greater relative proportion of phosphat of 
