OBSERVATIONS ON THE PREPARATIONS OF CONIUM. 
573 
carefully examined the sample of dried leaves used in the preparation of the 
tincture employed in my experiments. As I have, in a paper which has not yet 
appeared in the ‘Pharmaceutical Journal,’ described in detail the processes 
adopted, I will only mention here that I operated upon equal quantities of the 
dried leaf separated from the leafstalks, and of the leafstalks themselves; that 
both furnished an equal quantity of conia, and that this in each case did not 
amount to half a grain of impure conia from of the dried plant. In order 
to separate so small a quantity of the active principle, I was led to adopt a pro¬ 
cess which I believe will be found to yield a larger quantity of conia than any 
other. Having prepared an aqueous or spirituous extract of the plant with as 
little heat as possible, and of a syrupy consistence, I mix it, while warm, with 
an equal bulk of strong solution of caustic potash (1 pint to 3 of water), and 
then transfer it to a long tube, and agitate the mixture with its bulk of sether 
several times during twenty-four hours. The sether is then decanted, and the 
alkaline mixture washed again and again with fresh portions of sether, until the 
conia is completely removed. Two, or at most three washings are sufficient for 
this purpose. On distillation of the sethereal solution the conia, more or less 
pure, according as spirit or water has been used for exhausting the herb, 
remains. The impure conia is next treated with diluted sulphuric acid, which 
separates the alkaloid from oily or resinous impurities. From this solution of 
sulphate of conia, the base is separated in the usual way, viz. evaporation to a 
syrupy consistence, mixture with caustic potash, washing the mixture with 
ether, evaporation of the ether, and distillation of the conia in a current of 
hydrogen. In the preparation of the extract, a small quantity of dilute sul¬ 
phuric acid should be added to the tincture or infusion, in order to fix the conia 
before heat is applied. 
I satisfied myself that sether will entirely remove the conia from an alkalized 
extract, by the following experiment:—I took f ^iij of a dark brown mixture of 
extract and caustic potash, from which the conia had been completely removed 
by sether, and added to it a drop of conia dissolved in an excess of a dilute solu¬ 
tion of sulphuric acid. After thorough admixture, it was set by for a few hours, 
and then, finding that it still contained an excess of caustic potash, it was mixed 
with one-third its bulk of sether, and agitated for two minutes. The sether was 
removed as soon as it was separated, and the mixture washed again with the 
same volume of sether, and decanted without delay. On evaporating the sethereal 
solutions, nearly the whole of the original drop of conia was recovered. In this 
case the process was hastily performed, and no pains taken to thoroughly wash 
the exhausted extract. 
After making a number of comparative experiments of the above described 
method, and the usual mode of distillation with caustic potash, I find, as I have 
stated above, that the former is the most productive process when operating on 
small quantities. When strongly heated with caustic potash in the presence of 
organic matters, conia appears to undergo considerable decomposition. On ex¬ 
amination of the retort remainder, after the distillation of the alkaline fluid con¬ 
taining the conia, I have separated by means of sether, a definite crystalline 
compound which, as it possesses a strong odour and taste of tobacco, is probably 
a derivative of conia. It appears distinct, both in physical and chemical cha¬ 
racters, from conhydrin. As I have not yet completed my examination of it, I 
shall hope to say more about it in a future communication to the Journal. I 
call attention to it in this place, in order to elicit information respecting its 
relationship. A specimen lies upon the table. 
Having thus, satisfactorily I hope, explained why the particular tinctures 
employed in my experiments were inert, I hope we shall all be led to the con¬ 
clusion that the dried plant is wanting in the powers attributed to it, and that 
it should therefore be excluded from the Materia Medica. I would even apply 
