400 
POISONING BY STRYCHNIA. 
other agent, it is said, has been found to conduct itself in a 
similar way. 
It must be acknowledged that, in the application of these 
tests, with others that might be adduced, slight causes will 
often operate so as to alter the colours produced, whilst the 
shades of difference between some of them often deceive 
the inexperienced eye. On this account it is that the 
“ physiological test” has been preferred by some persons ; 
among whom we may mention Dr. Marshall Hall, who pro- 
poses employing frogs for this purpose. We have already 
transferred to our pages his experiments with these animals. 
But as frogs are not at all times to be got, other of the lower 
and smaller animals might be used. And since, in all toxi- 
cological investigations, inquiries should be instituted as to 
the symptoms presented before death took place, and as 
the alkaloids produce characteristic action on the organism, 
so unquestionably this becomes a very valuable adjuvant, as 
tending to confirm or otherwise the question of their exist- 
ence. Moreover, it may be accepted as a general fact, that 
those poisons which are most difficult of detection by chemi- 
cal means are most readily recognised by the effects produced 
by them on the living body. 
Since our last, the following has appeared in the Lancet : 
“ The Physiological Test for Strychnia . By Marshall Hall, 
m.d., f.r.s., &c. — Some years ago several cases of poison- 
ing by arsenic occurred in rapid succession. The career 
of crime was stayed by its being made publicly known that 
no poison was so readily or certainly detectible as arsenic, 
“ Arsenic is scarcely more detectible by chemical reagents 
than strychnia has proved to be by the physiological test 
which I recently published in the pages of the Lancet , 
“ Recently the 5000th part of a grain has been made mani- 
fest to a multitude of beholders at once, and so manifest that 
no visual object can be more conspicuous — an event very 
different from the fact of a mere change of colour. 
“The effect is produced, too, by the simplest means, such as 
our medical brethren in the country always have at hand. 
“The common frog , properly prepared, is not less sus- 
ceptible of the convulsive effects of galvanism than it is of 
the peculiar effects of strychnia. Of frogs the smaller ones 
are more susceptible than the larger, and these should be 
used recently taken from the pond — from the mud if 
possible. 
“The skin should be well dried by means ofblotting-paper 
The strychnia to be tested should be dissolved in as small a 
quantity of water as possible, and dropped on the back of the 
frog, so that it may become absorbed. 
