ON THE METHOD OF DISPLACEMENT. 191 
The extracts of narcotic plants, and those which contain 
volatile oils, both of which require great care in their prepa- 
ration, particularly the former, are rendered very superior by 
this process of lixiviation. They are perfectly soluble in cold 
water,and richer in active principles than those obtained by boil- 
ing water or alcohol. They yield transparent solutions, which 
is not the case with most of those made by heat, owing to the 
presence of fecula, which is necessarily left behind, when dis- 
placement is used, and should any vegetable albumen be pre- 
sent, it is coagulated by the subsequent heat in evaporating, 
and can easily be separated. 
From the results of a number of experiments, the quantity 
is very little, if at all, inferior to the old method, and the 
quality, in most instances, is decidedly better. Even Gen- 
tian, treated in this way, yields an equal amount of extract. 
Extract of Chamomile, as thus prepared, is a faithful 
representative of the plant. We have seen a variety of ex- 
tracts, of the narcotic class, made by M. Bottllay, of Paris, 
by displacement, and while we have tested their ready solu- 
bility, we have the most complete evidence of their therapeu- 
tic qualities, as tried by our physicians. 
Digitalis. — From experiments made with digitalis, we 
find that 100 parts of the leaves, subjected to the action of 
water, furnished, by 
Decoction and expression, 25 parts. 
Displacement with cold water, 24 " 
Maceration in alcohol, 31 " 
Displacement with alcohol, 30 " 
Maceration and displacement with alcohol, 32 " 
The product of the displacement treatment, with cold 
water, yielded a beautiful, translucid extract, brittle, deli- 
quescent, very soluble, and of great activity. The others 
contained more or less of resin and insoluble matters. By 
displacement, the first portions of liquid which escaped from 
the bottom of the funnel, were black, of a sirupy consistence^ 
and of an acrid, bitter taste. Those which followed were 
