152 Professor Dana on Morbid Animal Products. 
By the theory, urate of silver, containing Six prponteas 
of acid, consists o 
6 atoms uric acid 26 x6=156 
1 atom oxide silver - ~- 118. 
My analyses gives uric acid - ~- 157.33 
oxide of silver 118— 
Urate of ammonia, by the theory sae of 
Uric acid, (6 penbortens 26 x6). 
Ammonia, 1 proportion - 7 
My analysis gives, uric eS 156. 4 and ammonia, 17 
I regret that circumstances would not permit me to ex- 
amine a larger quantity of these calculi; they will not be 
distinguished from uric acid by the general tests proposed 
by Dr. Marcet, for the detection of this substance, for they 
are totally volatile before the blowpipe, and give a pink col- 
oured residuum with nitricacid; their colour, and the odour 
of ammonia developed by an alkali will distinguish them 
from uric acid calculi ; the effect of heat on the precipitate 
they a eae nitrate of eit is sufficient to reac 
Whe 125 
2, neat ap of some concretions foundina box; labelled 
_ * Coneretions growing in a Parrot, from Dr. Oliver, 
1759” i in the Nichols collection. 
Colour light grey, form irregular, rounded ; smooth to 
the touch ; splintery fracture; hard; cut without difficulty 
y the aul and exhibit a wax yellow colour internally. 
osed to heat, evolve an odour resembling that of 
ae bread; by continuing the heat, the odour becomes 
like that of burning feathers; a bulky ‘charcoal of difficult 
incineration remains, When exposed to the flame of a spirit 
lamp, they take fire and burn with a bright light. 
2, Sulphuric acid is blackened by them, and by the aid 
of heat it chars them; diluted sulphuric acid dissolves 
them, and the surface of the. solution becomes oily on the 
ition of ammonia 
3. When digested i in acetic acid, they become pulpy and 
SS oe and increased in bulk, and are dissolved in 
e The acetic acid solution affords a white precipitate 
Y prussiate of potash, hence these concretions consist of 
