BRITISH PHARMACEUTICAL CONFERENCE. 157 
of balsam of Peru, that he (Dr. P.) had used the oil of benzoin for the same purpose 
with the greatest success. 
Mr. Balkwiil inquired the best way of keeping cod-liver oil from becoming 
rancid. 
Mr. Bobbins volunteered a reply to this question, detailing the results of some ex¬ 
periments which he made. Portions of cod-liver oil being exposed to the air, and 
closely sealed up respectively, the former became rapidly rancid, but the latter was as 
sweet after ten years as when first put up. That this change of rancidity was accom¬ 
panied by absorption of oxygen, had been proved by Dr. AttfiekU* 
“ ON THE PROCESSES FOR PREPARING SOME OF THE TINCTURES OF THE 
PHARMACOPCEIA.S. BY MR. W. D. SAVAGE. 
[Abstract.^ 
u The author had experimented upon twelve different tinctures, making four speci¬ 
mens of each, by four different processes. In all cases the four specimens were made 
from the same parcel of raw material, at the same temperature and with the same spirit. 
The first process was maceration for 21 days ; the second, maceration for 7 days ; the 
third, maceration for 48 hours, with subsequent percolation ; the fourth, 21 clays’ ma¬ 
ceration, with the addition then of percolation. The relative value of these processes 
was ascertained by evaporating a similar portion of each tincture over a sand-bath and 
weighing the residue. The whole of the results were given in a tabular form. The 
author considered that maceration with subsequent percolation yielded the best re¬ 
sults, and that the period of maceration should, as a rule, be not less than 14 days.” 
Dr. Attfield said that if it were in our power to determine the quantity of active- 
principle in a tincture, this would be the line of search which we should follow. 
Under the inability to do this, the next best thing was to find w r lien the solvent 
ceased any longer to extract the drug. Following this plan, the late Dr. Burton took 
the specific gravities of tinctures after macerations for different periods of time, and thus 
fixed how long a contact was needful in each case. The author of this paper had 
adopted evaporation, drying and weighing, to attain the same result. The use of a 
sand-bath w r as open to objection as not being an equable source of heat, even in several 
experiments that might be conducted simultaneously ; an oil-batli should be used, 
and the extractive should, of course, be dried until it loses nothing upon repeated 
weighing. Similar experiments upon other tinctures were much needed. 
Mr. Schacht objected to the assumption that extractive was any guide to the quality 
of a tincture. Could any one suppose that tincture of orange-peel was better because 
containing much extractive ? ITe would instance an infusion of tea, the best being 
made by the free use of the leaf and very short digestion, and not by continuing it 
until much extractive was taken up. 
Mr. Bobbins would like to know more as to the frequency with which the author 
had agitated the tinctures during maceration. Mr. Hills had shown that so short a 
period as forty-eight hours would suffice, provided that agitation were correspondingly 
frequent. 
Dr. Edwards explained the highly ingenious process for combining maceration.- 
with both percolation and expression, which was lately introduced by Dr. Bedwood. 
Mr. Balkwill thought that the moral to be drawn from this paper was, that we- 
should adopt a uniform practice in the maceration of tinctures, or great variation in 
the product would result. 
“ ON THE CULTIVATION OF MEDICINAL PLANTS AT MITCHAM. 
BY MR. J. T. P. B. WARREN. 
[Abstract^] 
“ The author gave a list of the plants cultivated and the acreage they occupied. The 
yield of oil per acre varied with season and soil; lavender yielded 10 to 20 lb. per 
acre, the second year’s growth giving more than the first or third ; peppermint, 8 to 
12 lb., though much influenced by soil; 4 cwt. of chamomiles were obtained from an 
acre, and gave 8 lb. of oil; and pennyroyal afforded about 12 lb. of oil per acre. 
Mitcham produces annually 30,000 to 40,000 bushels of roses and about 11 tons of 
* Pliarm. Journ., 2nd ser. vol. ii. p. 116. 
VOL. VI. N 
