248 
ON EXTRACT ON HENBANE. 
it now is, and has been purposely kept without being moved or 
meddled with. It has lost the fine green color which it once pos- 
sessed, but on dissolving a few grains in liq. potassaB last evening, 
and comparing it with a similar solution of last year's extract, I 
could not perceive any difference in the strength. I believe that if 
the herbs were well dried and carefully kept for twelve months, 
they would then yield, by treating with water, an extract much 
stronger than any that can be made from the green plant, but such 
extracts do not keep well, and are very deliquescent. Great 
strength then is not the only requisite of a good extract ; it mat- 
ters little to prescriber or patient whether four or five grains be 
ordered or taken, but it is very inconvenient to both dispenser and 
patient to have a box of pills in less than a week becoming soft, 
and running into a mass, which must be the case unless some dry 
powder be used in making them, which of course does away with 
the advantage of the additional strength : it is moreover very im- 
portant that extracts should be of the same strength at one time 
of the year as at another, and such they cannot be unless they be 
made with every precaution to prevent change. Besides the ex- 
tract of hemlock, already mentioned, there are on the table three 
samples of extracts of henbane, made in the month of June, 1848, 
'49, and '50, which have been kept in pots merely tied over with 
brown paper, and have undergone no change worthy of notice, 
and this is the best proof I can give of the value of the process I 
have been describing. 
Mr. Bell agreed with the author of the paper in considering that 
the biennial plant yields a better extract than the annual. He be- 
lieved, however, that the annual plant was very generally used in 
consequence of its yielding a larger quantity of extract than the 
biennial. 
The Chairman corroborated Mr. Bell's statement, in reference 
to the relative quantities of extract obtained from the two varieties 
of henbane. He observed, with reference to the preservation of 
the extract, that the length of time during which it might be kept 
depended very much on the extent to which it was exposed to the 
air. Turning it from one pot to another would cause it to spoil 
sooner, by exposing a fresh surface. 
