Experiments on Manioc. 
137 
fatigue, the whipping, and the exertion made by the patients, 
by accelerating the circulation, produced an abundant per- 
spiration, and prevented the absorption of the poisonous prin- 
ciple. 
The facts just related leave no doubt as to the poisonous 
character of the root of the bitter manioc. Its active prin- 
ciple resides in the juice extracted by expression, and appears 
to be very soluble and volatile or destructible by the action 
of the heat used in preparing the pulp for food. It, there- 
fore, is of importance to ascertain the nature of this princi- 
ple. M. M. Souberan and Pelletier have already examined a 
small quantity of the juice ; but on account, in all proba- 
bility of the minute portion on which they operated, the 
juice on distillation only afforded them a smell of bitter al- 
monds, without any other indication of the presence of hydro- 
cyanic acid, a small quantity of uncrystallizable sugar, and 
an azotized substance. Having received a bottle of the juice 
of the bitter manioc from Dr. Sureau, sent with the greatest 
care, and accompanied with some of the distilled water of 
the same plant, I subjected these products to various trials, 
hoping that the juice, although very alterable, might still 
present some interesting peculiarities, and a portion of the 
active principle. The distilled water, giving no indication of 
hydrocyanic acid, nor any thing thing that was remarkable, 
I pass at once to the analysis of the juice. 
Analysis of the Juice. This fluid, obtained from the fresh 
pulp by expression, was of a greenish yellow colour, not very 
consistent, translucid, especially after filtration, which sepa- 
rated some amylaceous particles mixed with glutine. Its 
taste was somewhat bitter, and at the same time sapid and 
not disagreeable. When evaporated in the open air, it af- 
forded small but very distinct crystalline grains. 
Reagents demonstrated the presence of very little lime, 
but of a tolerably strong acid, alcohol produced viscous white 
flakes and barytes and nitrate of silver threw down precipi- 
tates. 
On exposing the juice to the action of heat, a sensible odour 
of hydrocyanic acid was disengaged, which was followed by 
Vol, I— No. 2 18 
