VESICULAR CALCULUS IN A RAT, &C. 283 
Having prepared some aconitina, the active principle of the 
aconitum napellus, I wished to try its effects on the animal sys- 
tem. Accident brought into iny way a living rat, so I gave him 
a small quantity, and the results were, twitching of the tendons, 
with convulsion and swelling of the abdomen. After death I 
opened him, and found the alimentary canal inflamed, and the 
brains and lungs gorged with blood. Perceiving that the neck of 
the bladder was much enlarged, 1 opened that viscus, and to my 
surprise found a calculus of immense size (compared with the 
rat), weighing rather more than three grains, in a crystalline 
state, with a surface roughed by three-sided pyramids, of a yel- 
low colour and loose texture. 
Analysis of the calculus gave, urate of ammonia, phosphate of 
lime, and ammoniacal phosphate of magnesia. When a small 
quantity was ignited strongly, it first assumed a grey and after- 
wards a white colour. When the white powder was gathered 
together, and a little hydrochloric acid added to it, there was a 
slight explosion, with a hissing noise attended by evolution of 
carbonic acid gas, and it instantaneously dissolved. 
This calculus is as large as one (in proportion) in a man 
weighing two ounces and a quarter. 
A CASE OF AMPUTATION OF THE PREPUCE OF 
A HORSE. 
Communicated by Mr. R. Read, of Crediton. 
About the middle of January 1836, a grey horse was sent to 
my infirmary, having a fungous excrescence on the prepuce, with 
a foetid and purulent discharge. On examination, 1 found a 
fungous growth springing from and encircling the prepuce, yet 
leaving room for the penis freely to protrude. I informed the 
owner that nothing short of excision would do any good ; but 
he being anxious that other means should be tried, I ordered a 
solution of the oxymuriate of mercury to be applied, and which 
was continued, with other caustics, for seven or eight weeks 
without amendment. 
The fungus still continuing to increase, on the 18th of May 
the horse was sent to me, in order that the tumour might be ex- 
cised. Its appearance was then horrible. It had increased in 
size to an extraordinary degree ; and there is no painter in the 
kingdom who could have made a better likeness than by com- 
paring it to a roasted fillet of veal, through the middle of which 
the penis projected. The fungus so strictured the penis, as to 
