580 
LEEDS CHEMISTS’ ASSOCIATION. 
Several members took part in the discussion, and the best thanks of the meeting were 
voted to the lecturer on the motion of Mr. Thompson, seconded by Mr. Bemrose (late 
Senior Bell Scholar). 
The Fifth Meeting was held on February 10 ; the President in the chair. 
Mr. Sturdy was elected an Associate. 
Mr. R. M. Atkinson read the paper of the evening, upon “Tinctures, and their Pre¬ 
paration by the B.P. Method of Percolation.” Mr. Atkinson referred to the combined 
system of maceration with percolation adopted by the B. P. for so large a number of 
tinctures, and expressed the want of some standard by which the pharmacist could test 
his operations. It was to contribute towards this supposed want that the experiments 
about to be detailed had been undertaken. The variation in the specific gravity of 
properly-made tinctures was much less than some persons had represented ; and in con¬ 
firmation of this the experiments of Mr. Laird, as reported to the British Pharmaceu¬ 
tical Conference, were quoted. The influence of light upon such tinctures as conium 
and digitalis was referred to, and the use of bottles of non-actinic glass advised. The 
nature of the deposit in tincture of rhubarb was next described. Proceeding to the 
process of the P. B., the author condemned the practice of some operators in using 
three-fourths of their spirit for the macerating process. He preferred to add to the solid 
ingredients enough spirit to form a thin paste, and after maceration for several days to 
add the remaining spirit in small and repeated quantities. Some operators have been led 
into error by overlooking the diminution in bulk which follows the dilution of alcohol 
with water. This amounts to 3*60 per cent, in the preparation of proof spirit. Tincture 
of opium, if macerated for several weeks according to the old practice of many chemists, 
certainly differs from the more expeditiously-made tincture of the B. P. Habitual 
laudanum-takers had often detected this difference, and complained of the alteration. 
Hence it seemed desirable to macerate for twenty-eight days at least. The paper con¬ 
cluded by presenting in a tabular form the results of many experiments in the prepara¬ 
tion of tinctures by the method of the B. P. 
Table giving Amount of Spirit required for each Pint of Tincture, with Specific Gravity , 
Weight of Solids Ordered, Weight of Marc Pressed, and Weight of Marc dried. 
Tinctures. 
Amount 
of spirit 
required. 
To 
make 
pints. 
Sp. gr. 
60°. 
Weight 
of solids 
used. 
Weight 
of wet 
marc. 
W eight 
of dried 
marc. 
OZ. 
dr. 
OZ 
gr. 
gr. 
gr. 
Assafcetidse . . 
20 
0 
1 
•8560 
2* 
0 
1533 
547 
Aurantii . . . 
20 
5 
1 
•9340 
2 
0 
876 
657 
Benzoin . . . 
17 
0 
1 
•8950 
4 
160 
438 
190 
Card. Co.. . . 
19 
1 
1 
•9569 
3 
60 
814 
446 
Camph. Co. . . 
20 
0 
1 
•9252 
0 
110 
24 
Cinchon. Co. 
21 
2 
1 
•9385 
3 
309 
1851 
1337 
55 55 • • 
22 
0 
1 
•9365 
3 
309 
1648 
1085 
Conii .... 
22 
0 
1 
•9265 
2 
219 
1204 
766 
■ Calumbee. . . 
21 
6 
1 
1252 
1095 
Digitalis . . . 
21 
1 
1 
•9365 
2 
219 
983 
598 
Hyoscyami . . 
21 
2 
1 
•9323 
2 
219 
1176 
657 
Gent. Co.. . . 
21 
0 
1 
•9415 
2 
219 
2080 
1204 
Lavand. Co. . . 
20 
4 
1 
•9194 
1 
162 
766 
398 
Sennae . . . 
20 
6 
1 
•9690 
5 
219 
1600 
1104 
Quassise . . . 
21 
5 
1 
•9210 
0 
328 
498 
250 
Opii .... 
20 
5 
1 
•9415 
1 
219 
306 
180 
Guaiaci . . . 
17 
5 
1 
•9285 
4 
0 
180 
135 
55 • • • 
18 
0 
1 
•9310 
4 
0 
303 
146 
Myrrhse . . . 
20 
3 
1 
•8463 
2 
219 
876 
618 
Rhei Co. . . . 
21 
4 
1 
•9307 
2 
328 
1204 
657 
Tolu .... 
18 
4 
1 
•8774 
2 
219 
20 
Nuc. Vom. . . 
21 
5 
1 
•8412 
2 
0 
1226 
794 
Jalapii . . . 
20 
7 
1 
•9364 
2 
219 
858 
508 
Lobeliae . . . 
21 
5 
1 
•9287 
2 
219 
1186 
730 
