167 
The memoir concluded by stating, that though the subject could 
not be very interesting to those devoted to the active study of natural 
science at the present day, it had its value to those who took pleasure 
in studying the progress of human knowledge. 
2. On a new Arrow-Poison from China. By Dr Christison. 
In a newspaper printed at Shanghae, in the spring of 1857, a 
wonderful account was given of a poison, which was said to he em- 
ployed in the interior of China for destroying the largest animals. 
Instant death was said to be produced, when an animal was struck 
in the trunk of the body with an arrow poisoned with it. Such was 
its potency, according to the opinion of the Chinese, that a scheme 
was said to have been set on foot for destroying the British army 
during the late w*ar, by bringing down to Canton the natives who 
were in the practice of using it. But the scheme was frustrated by 
peace being unfortunately proclaimed too soon. 
The poison, and apparently the plant also, are known by the 
Chinese name of Wu-Tsau , or Tiger-poison. The author received 
very lately from Dr Macgowan, an American physician residing at 
Shanghae, a specimen of the poison, and of the root of the plant 
from which it is prepared. The root presents all the characters of 
an Aconitum on a very small scale. This corresponds with the con- 
clusion to be drawn from the characters of a few leaves which were 
also sent, and* which scarcely differ from those of Aconitum ferox. 
A farther proof is, that the root produces in an intense degree the 
very singular combination of numbness and tingling, which is occa- 
sioned by chewing the root of any of the active aconites known in 
Europe, such as A. ATapellus , ferox , sinense, or uncinatum. The 
poison itself, contained in a little porcelain bottle, is obviously a very 
well prepared extract ; and, if not entirely composed of the extract 
of the wu-tsau root, at all events must contain it largely, for a very 
minute quantity produces the most intense tingling and numbness 
of the tongue and lips after it is chewed. 
There can be no doubt, therefore, that the wu-tsau poison must 
be extremely energetic. But the author objected to the admission 
that either this or any other arrow-poison can produce instant death, 
as is often stated by travellers. Every poison, however energetic, 
must be absorbed into the blood before it can act. Even from a 
