596 NOTES AND ABSTRACTS IN CHEMISTRY AND PHARMACY. 
powdered and kept in the manner above described, I believe there would be 
much more certainty in administering the preparations made from them. I 
entirely omit from this consideration the question as to what deterioration 
plants undergo by drying at all: that some, at all events, do suffer seriously, I 
think cannot be disputed, as the Ranunculus acris proves; which, when eaten 
fresh by cattle produces poisonous effects, but when dried with hay is afterwards 
eaten with impunity. 
One serious objection to the adoption of the above mode of preserving leaves, 
etc., is the fact that the great mass of chemists buy their henbane, foxglove, 
etc., of wholesale houses at all times of the year, as they require them ; in such 
cases I question whether any good would be obtained by using the plan. The 
only alternative then is for wholesale houses to do it, or for country chemists 
who live in neighbourhoods where medicinal plants abound, to prepare them 
and supply to those who will buy them. 
I am, yours, 
T. M. Gissing. 
EM PL A ST HUM BELLADONNA, P.B. 
TO THE EDITORS OF THE PHARMACEUTICAL JOURNAL. 
Gentlemen,—Sufficient time has now elapsed to enable all practical pharma¬ 
ceutists to give their experience in making the preparations of the British 
Pharmacopoeia. I shall feel much obliged if any of them will favour me, either 
by letter or through the Journal, with their observations upon the Emplas- 
trum Belladonnee. 
1st. Does the quantity of extract taken up by the spirit vary at different 
times of the year ? 
2nd. Is it affected in colour or quantity by the use of methylated spirit ? 
If so, in what way ? 
3rd. What is the average quantity taken up by the spirit ? 
I am, yours truly, 
T. W. Gissing. 
Wakefield,, March 9, 1869. 
NOTES AND ABSTRACTS IN CHEMISTRY AND PHARMACY. 
BY C. H. WOOD, F.C.S. 
A New Vacuum Apparatus. A Vacuum Filter. 
In a recent number of this Journal an account was given of an article by 
Professor Bunsen, “ On the Washing of Precipitates,”* in which reference was 
made to a new vacuum filter devised and employed by Bunsen for promoting 
rapid filtration. Although the apparatus was especially intended for filtration, 
it is equally applicable to evaporation and general chemical purposes. From its 
cheap and adaptable nature it is likely to find its way into every laboratory 
that possesses a good supply of water, and a sufficient height above the ground. 
It is, in fact, a simple modification of the well-known Sprengel air-pump, water 
being employed in the place of mercury. A stream of water, falling down a 
pipe thirty or forty feet in depth, sucks the air from any vessel communicating 
with the top of the pipe, and produces the vacuum. A rarefaction within a 
half or a quarter of an inch of mercurial pressure is easily obtained. The 
arrangement of the pump is shown in the figure. 
* Annalen der Cliemie, and Phil. Mag., Jau. 1869. 
