246 
ON EXTRACT OF HENBANE. 
stem, it will be perceived that the weight then resides chiefly in 
the top. Of the immature plant but little is met with in the mar- 
ket : a description of it is obviously impossible, as I should call it 
too young at any period before the one first mentioned ; the ex- 
tract yielded by it I shall describe presently. Much has been said 
at various times about the relative strength of the extracts made 
from annual and biennial hyoscyamus, and I believe that the 
opinion is gaining ground that they may be used indiscriminately. 
It is not my intention to dwell upon this part of the subject now, 
but I may remark in passing that the physical characters of the 
two plants and their extracts differ considerably, and in the ab- 
sence of proof, I have no hesitation in deciding in favor of the 
biennial — such then is the plant I always use, and to which my 
present remarks refer. 
I now come to the preparation of the extract. The market bun- 
dles, which are always more or less heated, should be opened im- 
mediately they are received, and the herb spread in a cool place ; 
the leaves, flowers, soft stalks, and seed vessels should then be 
stripped from the large hard stalks as quickly as possible, ground 
in a mill (without being sprinkled with water as directed by the 
Pharmacopoeia, as there is already more of that ingredient than 
the careful operator desires) and the juice expressed, strained 
through some coarse material, and conveyed to the evaporating 
pans. I may here remark, that the practiced eye can predict the 
quality and character of the extract by looking at the juice. The 
juice yielded by the immature plant is of a bright grass green 
color; that by the plant of proper age is of a deep dull green color, 
such as would be produced by a certain mixture of brown and 
green ; and that by the plant when too old is of a brown color, 
with some green coloring-matter floating in it, which speedily set- 
tles to the bottom. In a valuable paper read in this room on the 
13th of November, the process of evaporation was so ably discuss- 
ed that little remains to be said on the subject. I believe the best 
methods, and which are always at command, to be a water-bath, 
or the passing a current of warm air over the surface of the juice. 
Among the advantages of thfs latter process stated by Mr. Archer, 
there is, however, one with which I beg to differ; he says, " The 
evaporating liquid requires no stirring, or other attention, from 
