396 
POISONING BY STRYCHNIA. 
Thibierge find that perchloride of gold is a more decisive 
test of certain vegetable alkalies than the double chloride of 
sodium and gold already employed for this purpose. The 
following are the colours of the precipitates which it pro- 
duces with the salts of the annexed alkalies dissolved in 
water : quinine, buff-coloured ; cinchonine, sulphur-yellow ; 
morphine, yellow, then bluish, and lastly violet; in this last 
state the gold is reduced, and the precipitate is insoluble in 
water, alcohol, the caustic alkalies, and sulphuric, nitric or 
hydrochloric acids ; it forms with aqua regia a solution which 
is precipitated by protosulphate of iron : brucine, coffee, and 
then chocolate-brown ; strychnine, canary-yellow ; veratrine, 
slightly greenish-yellows 
All these precipitates, with the exception mentioned, are 
very soluble in alcohol, insoluble in aether, and slightly soluble 
in water. They appear to be combinations of gold, chlorine, 
and the vegetable alkali, for their alcoholic solutions treated 
with tannin give a greenish-blue precipitate of reduced gold ; 
if the solution be filtered, and the alcohol evaporated by 
heat, a precipitate of tannate of the alkali employed is formed. 
The liquor again filtered, gives with nitrate of silver, a 
white precipitate insoluble in nitric acid, but soluble in 
ammonia. 
Among the reactions of chloride of gold, there are two 
which to the authors appear to be especially important ; they 
are those which occur w ith morphine and brucine ; these are 
sufficiently marked to prevent these alkalies from being mis- 
taken for each other, and also yield pretty good character- 
istics for distinguishing brucine from strychnine. 
MM. Larocque and Thibierge detail also various experi- 
ments on the modes of detecting opium proposed by Dr. 
Christison, and they mention that their results differ much 
from his. They state that these differences may arise from 
three causes, — 1st, the inequality of the composition of the 
opium of commerce ; 2dly, the analytical process employed 
by Dr. Christison, which consisted in decomposing the meco- 
nate of lead by sulphuretted hydrogen — this the authors 
show r frequently masks the meconic acid, and that it can 
only be detected by decomposing the meconate of lead with 
dilute sulphuric acid ; 3dly, the variable nature of the liquids 
with w 7 hich opium is mixed. 
The authors have also, as the results of their experiments, 
arrived at the following conclusions : 
1st. By the aid of reagents it is possible to determine the 
presence of morphine, strychnine, and brucine in substances, 
which, after being mixed w 7 ith the salts of these alkalies, 
