62 
PROCEEDINGS OF SOCIETIES. 
Royaut Society, June 12th, 1856. 
Lord Wrottesley, President, in the chair. 
Letter from Dr. W. Brrp Herapatu to Professor Stokes, 
“ On the Detection of Strychnia by the formation of Iodo- 
strychnia.’ Communicated by Professor Stoxss, Sec. 
R.S. 
Bristol, June 7th, 1856. 
My prar Srr,—Will you do me the favour to announce 
to the Royal Society, that I have been engaged during some 
time past in the application of my discovery of the optical 
properties of iodo-strychnia to the detection of this alkaloid 
in medico-legal inquiries? I find it perfectly possible to 
recognize the 10,000th part of a grain of strychnia in pure 
solutions by this method, even when experimenting on very 
minute quantities. In one experiment I took z,55th of a 
grain only, and having produced ten crystals of nearly 
equal size, of course each one, possessing distinct and 
decided optical properties, could not represent more than the 
zodooth part of a grain; in fact, it really represents much 
less, Imasmuch as one portion of the strychnia is converted 
by substitution into a soluble hydriodate, and of course 
remains dissolved in the liquid. 
I had hoped to have been able to complete this matter 
during this summer, but I now find it impossible to do so in 
time for this session of the Royal Society. I trust to be 
able to do so before Christmas, however. Will you oblige 
me by getting this notice inserted in the ‘ Proceedings,’ as a 
new test for strychnia at this juncture possesses considerable 
interest, the colour-tests having been so dubiously spoken of 
recently by toxicologists ? 
In order to operate in this experiment, it is merely neces- 
sary to use diluted spirit of wine, about in the proportions of 
one part of spirit to three of water, as the solvent medium, 
and to employ the smallest possible quantity of the tincture 
of iodine as the reagent, and after applying heat for a short 
time, to set in repose. On spontaneous evaporation or cool- 
ing, the optical crystals deposit themselves, and may be 
recognised by the polarizing microscope, according to the 
