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Art. 'XT^.'^Mesearches on Hydrocyanic Acid and Opium, with 
rtference to their Counter-Poisons. By John Murray, 
Esq. F. L. S. M. W. S. &c. Communicated by the Author. 
Xn June 1815, a paper of mine was read to the Linnean So- 
ciety, developing a simple and apparently decisive method of as- 
certaining the sedative virtues of vegetable juices and their coun- 
ter-agents. 
The sciatic nerves of the prepared frog were taken up by a 
silver probe, and moistened with the tincture, and the result in- 
dicated the sedative power or its obverse ; the degree was deter- 
mined by the specific gravity of the solution employed, and the 
power measured by the duration of the period required to pro- 
duce its maximum effect. 
It would be superfluous now to describe what has already been 
amply detailed. It was clearly proved from the result, that a sus- 
pension of the voltaic excitement, more or less decided, was the 
consequence of certain vegetable juices, and that in such as were 
operative in this manner, acetic acid was found to be a counter- 
agent. 
It may be worthy of remark in this place, that discoveries 
have since manifested new alkaline bases, characterised by speci- 
fic characters in such as having produced a sedative elFect, were 
neutralised by acetic acid, as morphia, atropia, &c. 
The following paper is intended simply to detail the results 
of some experiments, instituted with reference to the discovery 
of counter-poisons to their agency on the system. Facts are 
soon detailed ; and it is not necessary that they be amplified or 
extended by unnecessary details. The truths gleaned from ac- 
tual experiment are immutable, while the consequences which 
may be deduced in support of a theory, may soon be overlook- 
ed in the progression of intelligence. 
I had always found, that the violent headach which sometimes 
occurred in preparing hydrocyanic or prussic acid, was relieved 
and removed by ammonia, which induced me to think that the 
antidote to that acid, and virulent and formidable poison, might 
be found in ammonia. 
