92 
Proceedings of the Royal Society, 
Monday , 15 th March 1858. 
The Right Rev. Bishop TERROT, V.P., in the Chair. 
The following Communications were read 
1. Note on the use of Subacetate of Lead as a means of se- 
parating some of the Vegetable Alkaloids. By Thomas 
Anderson, M.D., F.R.S.E. 
In a paper on the crystalline constituents of opium, read before 
the Royal Society of Edinburgh, I described a process for separating 
thebaine from papaverine and narcotine, with which it occurs mixed 
in the opium liquor I examined. This process consisted in convert- 
ing the mixed bases into acetates, and adding to the solution an ex- 
cess of subacetate of lead, by which the feebler bases are precipitated, 
and the stronger thebaine left in solution. 
As it is familiarly known that in those plants in which alkaloids 
are found, they rarely occur singly, but are generally associated in 
groups of two or more, often very closely allied in their properties, 
and consequently require for their separation, processes of consi- 
derable complexity, I have been induced to make a few experi- 
ments, with the view of ascertaining whether the method I had 
applied with success to the opium bases could be used for other sub- 
stances. These observations I offer, not as exhausting the subject, 
but merely as an indication of a path which may be followed by 
those engaged in the examination of the natural bases with some 
prospect of success. 
When a dilute solution of acetate of strychnine, containing an excess 
of acid, is mixed with a saturated solution of subacetate of lead, until 
its reaction becomes alkaline, and a further quantity of the lead- 
salt added, the fluid at first remains perfectly clear ; but after some 
time minute crystals of strychnine begin to be deposited, and go on 
gradually increasing in quantity for four-and-twenty hours. If the 
solution be highly diluted, the strychnine is deposited slowly, and 
then appears in very regular crystals, occasionally of considerable 
size. Concentrated solutions, if violently agitated, are rapidly filled 
with precipitated strychnine. 
If brucine be treated in a similar manner, the solution remains 
