ON THE PREPARATION OF VEGETABLE ALKALOIDS. 243 
For the preparation of columbine, strychine, and colocynthine, 
he operated as follows: 
Having deposited in the part of a funnel a layer of well-washed 
charcoal, he placed the respective substances (previously moisten- 
ed) upon it, and, by percolation with water, exhausted them of 
their active principles, which, however, were ceded by the water in 
passing through the stratum of charcoal. The charcoal was then 
treated as previously described, and the alcohol yielded, by spon- 
taneous evaporation, crystals of the respective bases. 
A remarkable property connected with the last-mentioned bases 
is, that by a long-continued stream of water they may be redissolved 
from out the charcoal which had absorbed them, and this solution 
being filtered through charcoal, they again combine with the lat- 
ter substance. M. L. did not find this to be the case with any 
other of the bases which he examined. 
By similar manipulation to the above was obtained an alkaloid 
which was the subject of an interesting paper from Mr. Bastick at 
the last meeting, but which, I think, that gentleman is mistaken 
in suppossing to be a new base j for so long age as 1848, M. Le- 
bourdais published an account of arnicina, which he described as 
" a substance having the aspect and consistence of Venice-turpen- 
tine, slightly soluble in water, but the small quantity dissolved 
communicating to it nevertheless a bitter taste : soluble in all pro- 
portions in alcohol ; and this solution, by spontaneous evaporation 
under various circumstances, invariably leaving a residue having 
the aspect and consistence above described." 
In a series of experiments which I made shortly after the publi- 
cation of M. L.'s process, I found that as a general rule the alka- 
loids of those substances not containing much colouring matter 
may be most conveniently prepared by the simple percolation 
through charcoal, &c. ; while those rich in colouring matter require 
previous precipitation by acetate of lead, excepting of course those 
substances (as the arnica) whose base is precipitated by this salt. 
I also found some slight variation of the above process necessary 
for obtaining certain of the alkaloids in a crystallized form. Thus, 
in the preparation of atropine, I found it necessary to add a small 
quantity of water to the alcohol, and to evaporate only till the 
liquid assumed a milky appearance ; with this slight variation, 
however, I obtained atropine by the above process with compara- 
