442 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. [December 7 ,167*. 
of these so-called 'green extracts, it is not so very 
easy to distinguish between one and another, as ex¬ 
emplified by the answers of the candidates who come 
up for examination in pharmacy. I venture to state 
that it will not be more difficult to distinguish these 
proposed purified extracts than it is with those 
already in use, for, although the colour will be 
different, their characteristic odours will be retained. 
To the next objection, that of increased strength, 
any inconvenience which might arise from that 
source will be more than counterbalanced by the 
very important consideration of uniformity of strength 
of these preparations; and in order to facilitate the 
use of these pure extracts I might be allowed to sug¬ 
gest their employment in the form of liquid extracts ; 
hemlock, however, should be excluded on account 
of the volatile nature of its alkaloid. 
In order to prepare these fluid extracts, it will be 
necessary to continue the evaporation until reduced 
to dryness, before they are converted into the fluid 
state, and of course the addition of about a fourth part 
of rectified spirit will be required to preserve them. 
I have not made any of these solutions, therefore 
am not prepared to say of what strength they should 
be made. 
They would be more definite in strength than their 
corresponding tinctures, they would cost less, and 
the ease with which they could be prepared would, I 
am sure, be a boon to the pharmacist as well as to 
the medical man. 
The increased tendency of these extracts to deli¬ 
quesce can be met by making them firmer than those 
in use at present, and by keeping them in pots better 
secured than those commonly used. For the dis¬ 
pensing counter, strong glass jars with ground- 
glass lids would be found to answer well; and when 
made [into pills, the apt dispenser will not be at a 
loss to protect them from the action of the air. 
[The discussion upon this paper is printed at p. 458.] 
APPARATUS FOR MACERATING.* 
submitting it to successive contact with fresh por¬ 
tions of the menstruum. This is easily done when 
spirit is the solvent and the drug is in a state of 
moderately fine powder, but according to my ex¬ 
perience fit is not easily accomplished with water, 
which will neither penetrate ingredients in the pow¬ 
dered state nor exhaust them by passing through 
if they are not in a state of powder. A series of 
cones is, therefore, used, amongst which the total 
quantity of the substance operated upon is divided, 
and water is passed through the whole series, allow¬ 
ing sufficient time (determined by the character of 
the drug) for maceration upon each. When the 
model was previously exhibited, I thought that eight 
cones would prove sufficient for all substances; but 
I have since found it advantageous to employ at 
least sixteen cones wdien operating upon cinchona 
bark, and this number enables me to submit each 
portion of bark to sixteen macerations, and. to 
effect a very complete exhaustion without using 
more water than would be required for a single ma¬ 
ceration of the whole quantity. The completeness 
of the exhaustion is shown by the sp. gr. of the 
several infusions, of which it will only be necessary 
upon this occasion to quote the first and last taken 
from laboratory notes of two operations upon dif¬ 
ferent samples of cinchona :— 
Sample A. sp. gr. 
1st Liquor after passing through 10 cones 103d 
10th „ „ „ 1002 
Sample B. 
1st Liquor after passing through 10 cones 1080 
10th „ „ „ 1002 
I may mention that although sample B. proved so 
rich in extractive, the quality of the result was not 
considered satisfactory, and I agree with Mr. Um- 
ney, that cinchona barks suitable for fluid extract 
do not yield these large results. 
The relatively small exposure to heat and oxidation 
during evaporation of the smaller quantity of liquid 
employed under these circumstances materially af¬ 
fects the quality of the product. 
EY RICHARD W. GILES. 
It has been suggested to me that it would be de¬ 
sirable to give some explanation of the model re¬ 
presenting the simple arrangement which I have 
now presented to the museum of the Society, 
adopted for many years with increased satisfac¬ 
tion, for the exhaustion of drugs in the prepara¬ 
tion of extracts, liquors, syrups, etc.; but as this 
has been already done when the same model was 
exhibited at Nottingham on the occasion of the 
Pharmaceutical Conference held there in 1866, I 
shall content myself with a very brief general de¬ 
scription now, referring, for more detailed informa¬ 
tion, to former notices in the Pharmaceutical Jour¬ 
nal,! and supplementing those communications by 
some unpublished notes on the preparation of extract 
of rhubarb, in which the present macerating process 
was employed. 
The object of the apparatus is to obtain re¬ 
sults similar to those which are effected by well- 
conducted percolation, viz., the exhaustion of the 
drug with the minimum volume of solvent by 
* Read at the Evening Meeting of the Pharmaceutical 
.Society of Great Britain, December I, 1872. 
f See particularly vol. viii. p. 220 (2nd Series). 
The sketch represents a stand of eight cones, and 
eight receivers placed beneath the cones to receive 
the infusions at each running off. 
Each cone is about four gallons ca¬ 
pacity, and is provided with a movable 
strainer fitting the delivery end, which 
is secured during maceration by a cork. 
When the cork is withdrawn, the liquor 
flows through the strainer. Cinchona 
bark is an extreme example of difficult 
exhaustion. In operating upon other substances 
I use fewer cones—sometimes ten, sometimes four, 
sometimes only two. In the preparation of the 
sample of extract rhubarb now submitted, 4 lb. 
sliced rhubarb were divided amongst four cones and 
treated in the following manner. 
