314 
ON HYDROCYANIC ACID. 
effect produced on other animals, have been more limited, 1 have 
no doubt but such would be the result in them, and, in all proba- 
bility, the same result might be looked for in its action as a poison 
upon man. Upon man it is impossible to make experiments; and 
the few cases in which it may be taken, either by accident or de- 
sign, would not allow any competent person to be present to note 
with sufficient accuracy its effects; therefore precise records of 
its action upon any of the lower animals become valuable. It is 
with this object that I detail the results of my observations upon 
eight cases arising during my course of practice in the last four- 
teen years, in which I have administered it as a poison : their 
accuracy I can with confidence assert. 
I shall divide these eight cases into two portions; first, five 
horses and one dog, which were not affected with any organic dis- 
ease, or lesion of the sensorium or nervous system, which could be 
supposed to have any influence upon the action of a poisonous 
agent, and may be, I consider, taken as fair cases for testing the 
effect upon animals in ordinary health. In the second, there are 
two cases in which the results are different, and afford points for 
deep consideration ; the one, more especially, of concussion to the 
brain — the other was disease of the nervous system. These two 
cases I shall detail more at length. 
The first five cases may be considered together as one, as the 
results were so similar that individual description would only be 
a repetition 
To ascertain whether death could not be produced more rapidly 
by injecting the whole of the poison at once into the circulating 
system than by absorption from the mouth or fauces, or as vapour 
from the surface of the bronchial tubes, I threw into the jugular 
vein six drachms of Scheele’s prussic acid, and found that there 
was no difference either in the effect produced or in the period of 
action : I have adopted both methods about equally, and have 
found no perceptible difference. , 
The acid employed has always been of Scheele’s medicinal 
strength. I have also given one ounce ; but by the larger quan- 
tity I have not been able to trace any increased action. I there- 
fore conclude that, for horses, six drachms is a full dose to pro- 
duce death under ordinary states of health. I should observe, 
that the ages and sizes of the horses were various; but mere 
bulk of frame has little or no effect on the quantity required 
to produce death. I am, however, disposed to believe that the 
high development of sensorial power will be found to have an 
influence. 
The symptoms: — First, intense vertigo, immediately falling 
down, succeeded by greatly excited action of all the involuntary 
