432 
COLOUR-TESTS FOR STRYCHNIA, ETC. 
do this without showing that an esteemed medico-legal 
authority had made a mistake in reference to a reaction, and 
an oversight in rendering the words of a French author. 
I may add, that on comparing the extract of nux vomica 
with a specimen of curara poison, for which I am indebted to 
the kindness of Mr. Morson, and with the brown powder 
scraped from an arrow tipped with the same poison, and 
forming one of a collection kindly presented to me by 
Mr. Stone, of the College of Surgeons, I find no resemblance 
between the one extract and the other, except in the property 
of intense bitterness. The woorara poison imparts to strong 
sulphuric acid a greenish-brown tint, and the nux vomica a 
pink colour; while strong nitric acid, which turns the first 
to a pale, dirty yellow, changes the second to a very distinct 
orange colour. The addition to the solution in sulphuric acid 
of bichromate of potash produces less effect on the colour of 
the curara than takes place with the extract of nux vomica. 
If the woorara really contained any alkaloid capable of 
developing with sulphuric and nitric acids the deep rich 
colours attributed to it, I think that some approach to those 
colours might be expected in the extract itself. 
I may conclude this part of my subject by expressing my 
firm conviction that to the colour-tests applied in the manner 
1 have recommended, there is no valid logical objection; and 
that though a negative result is not conclusive of the absence 
of strychnia, a positive result (by which I must be understood 
to mean the development of a rich blue colour on stirring the 
colour-developing substances into a spot first treated with 
sulphuric acid without change of colour, the rich blue colour 
in question passing, after a few seconds, into other colours) 
affords undeniable proof of its presence. 
In my next, and last communication, I shall endeavour 
to discriminate the principal alkaloids from each other, 
and to represent the differences between them by convenient 
tabular forms. 
[To be continued') 
