110 
ON CORTEX PRUNI VIRGINIANS. 
medies. Uniting with a tonic power the property of calming irri- 
tation and diminishing nervous excitability, it is admirably 
adapted to the treatment of diseases in which a debilitated con- 
dition of the stomach, or of the system, is united with general or 
local irritation. When largely taken, it is said to diminish the 
action of the heart, an effect ascribable to the hydrocyanic acid 
which it affords. The remedy is highly useful in the hectic fever 
of scrofula and consumption, in the treatment of which it has 
long been a favorite with many American practitioners." It is 
very useful as an ingredient of compounds for the remedy of pul- 
monary complaints, and has also been resorted to in cases of 
dyspepsia and in the general debility which often succeeds in- 
flammatory diseases. 
This bark being undoubtedly an important article to the 
physician, I undertook a few experiments with a view towards 
ascertaining at what season its properties (which depend princi- 
pally for their efficacy on the amount of prussic acid which it 
will yield) exist in greatest perfection, and consequently when the 
bark is best adapted for collection. For this purpose I procured at 
intervals during the season in which it is brought to market for sale, 
portions of the inner bark from the same tree, (or from trees of 
apparently the same age,) and from portions of the largest 
branches of about the same age, which, being carefully dried and 
deprived of the epidermis, were bruised, macerated for a short 
time with water, and distilled in a close vessel ; the product was 
treated with weak solution of nitrate of silver, which, reacting 
with the prussic acid in the solution, formed a precipitate of cya- 
nide of silver ; this being carefully washed, dried and weighed, the 
quantity of hyodrocyanic acid in each portion of bark was esti- 
mated by the ratio of chemical equivalents. The distillate was 
also treated with a strong alkaline solution, and afterwards with 
a weak solution of nitrate of silver in the manner proposed by M. 
Liebig, (See American Journal of Pharmacy, vol. xxiii. page 253) 
but the results coinciding very closely with those obtained by the 
former process, it was deemed unnecessary to enumerate them. 
The results obtained from these experiments, with the dates at 
which the bark was collected, may be seen by the following 
statement. 
