LIVERPOOL CHEMISTS’ ASSOCIATION. 
359 
(Mr. Symes) thought that some of this was always driven off during the heating, and 
it was quite possible that a small amount of the cantharidine might also be removed 
during the volatilization of the acid. Calcis phosph.: in the B.P. test it states, that 
“the solution in nitric acid continues clear when an excess of acetate of soda is added.” 
If the solutions are dilute, such is the case; hut if concentrated , a precipitate occurs, 
even though the phosphate is pure. Oxymel scillae: the B. P. process, although appa¬ 
rently simple, is a very troublesome one, just calculated to take its preparation out of 
the pharmaceutist’s hands. During evaporation the product must be allowed to cool 
frequently, that the sp. g. might be taken ; this course would not be practicable except 
for large quantities ; the P.L. process answered very well, why alter it for a worse one? 
Syr. ferri phosph.: Mr. Symes considered this formula commenced with one error and 
ended with another. He thought the use of granulated sulphate of iron a mistake ; it 
possesses no advantages over the ordinary pure sulphate, except the doubtful one of 
spoiling much more readily. The product which “ should measure exactly twelve fluid 
ounces” never does so ; if the directions are followed carefully, barely eleven ounces are 
obtained. Should the quantity be left thus, or made up with what? is a question the 
Pharmacopoeia leaves unanswered. 
Mr. Abraham agreed with Mr. Symes in several points, but considered that there was 
no need to lose cantharidine or acetic acid in preparing acetum cantharidis, as the pro¬ 
cess might be conducted in a closed vessel. In other preparations in which cantharidis 
are used, such as charta epipastica and emplastrum cantharides, a high temperature is 
employed without injury to the product. 
Mr. A. Normax Tate then read a short paper on “ Tincture of Quinine.” It 
has been frequently mentioned to me that tincture of quinine did not contain the 
quantity of quinine ordered by the Pharmacopoeia, and I have examined several samples, 
obtained from different shops, some of which contained the proper proportion, or very 
nearly so, and others not. In those samples that were deficient the quantity of quinine 
varied from three to five grains per ounce of tincture. From what I have noticed in 
this tincture, it appears to me that the formula of the Pharmacopoeia is not altogether 
satisfactory, and for the following reasons :— 
It has been stated that it is impossible to dissolve the whole of the quinine ordered 
by the Pharmacopoeia, and that a large proportion remains undissolved! This, how¬ 
ever, is not the case ; for, if the directions are properly carried out, a very small residue 
is left, and this, I believe, is owing to the formation of tannate of quinine, which is 
separated in the filtration. But, notwithstanding that the greater portion of the quinine 
is taken up when the directions are followed, it does not, under all circumstances, re¬ 
main in solution. I have with me a sample of tincture of quinine, prepared strictly 
according to the directions of the Pharmacopoeia. With the exception of a mere trace, 
the whole of the quinine ordered was dissolved, and, on filtration, this trace was sepa¬ 
rated, and a clear tincture obtained. But you will see that a good proportion of the 
quinine is now not in solution. It has been deposited since it was placed in the bottle, 
and this bottle is only one of several filled at the same time, all of which now present 
the same appearance. The reason of this is, that the quantity of quinine soluble in 
tincture of orange by the aid of a gentle heat, as ordered by the Pharmacopoeia, is 
greater than can be retained in solution under all circumstances to which the tincture is 
liable to be exposed. For instance, the deposit in the example I have shown you was 
thrown down during a night when the temperature fell some few degrees. It was clear and 
bright over-night, and in the morning the deposit was observed. Although the quinine 
can be redissolved by the aid of a gentle heat, yet it does not appear to redissolve so 
readily as it at first dissolves. Now, I think this is a drawback to the successful use of 
tincture of quinine. The strength of it should not vary, and for many reasons it is 
advisable that the quinine should always be in solution. Disulphate of quinine is soluble 
in about GO parts of rectified spirit, in about 740 parts of cold, and in about 30 parts of 
boiling water. Therefore, unless there is something else present in the tincture of 
orange to increase the solubility, there is an excess of quinine; the formula for tincture 
of orange, being 2 oz. of orange-peel and 1 pint of proof spirit, and this makes the 
quantity of tincture in which 1G0 grains of disulphate of quinine are ordered to be dis¬ 
solved. This is in the proportion of 1 part of quinine to 60 parts of proof spirit, which 
is not capable of dissolving so much quinine as rectified spirit. The solubility of 
quinine in tincture of orange is, however, said to be increased by the presence of a vege- 
