574 
LECTURES ON THE BRITISH PHARMACOPOEIA. 
Mr. Hemingway lias pointed out to me an omission in tlie formula of Lini- 
mentum Cantharidis. Eight ounces of powdered cantkarides are to be mace¬ 
rated in four fluid ounces of acetic acid for twenty-four hours, and tben per¬ 
colated with a pint of ether, till twenty fluid ounces of liniment are obtained. 
Now- Mr. Hemingwaj 7- has found that, owing to the retention of liquid in the 
percolator by the large bulk of cantharides ordered, only fifteen fluid ounces 
of liniment are obtained. Nothing is said about pressing the marc as directed 
in the preparation of tinctures. Nor will pharmaceutists be likely to adopt 
this mode of making up the pint of liniment. Eor although Mr. Hemingway 
thus obtained an additional two and a half ounces of liquid, he did so at the 
expense of a blistered face, owing to the evaporation of the cantharidin along 
with the vapour of ether during manipulation. He was, moreover, still two 
and a half ounces short of his pint of liniment. The authors of the Pharma¬ 
copoeia would probably, under these circumstances, direct that “Ether, one 
pint, or a sufficiency” be used, so that the percolation, or displacement, be 
continued until the product measures twenty fluid ounces. 
Linimentum Hydrargyri is now made by the Dublin process, in which mercurial 
ointment is to be dissolved in camphor liniment u with a gentle heat.” Deane 
pointed out (Pharm. Journ. vol. xviii. p. 310) the omission in the London process of 
directions to apply “a gentle heat” (Boucher also, Pharm. Journ. 2nd ser. vol. i. 
p. 15); otherwise, the only difference between the London and Dublin liniments is 
that the latter contains oil in the place of the lard of the former. This difference 
can scarcely account for the fact, that of the specimens of this liniment shown at 
the International Exhibition, that by the Dublin process soon spoiled, while the 
London preparation is unchanged to the present time (Pharm. Journ. 2nd ser. 
vol. v. p. 476). It remains for some pharmaceutist to ascertain by experiment if 
such a result is constant or only accidental, in order that in a future edition of 
the Pharmacopoeia the present formula may be retained, or substituted by the 
London one, or exchanged for a slightly modified one. 
Linimentum Saponis is essentially that of the London Pharmacopoeia. Deane 
(Pharm. Journ. vol. xviii. p. 462) stated it to be the best, provided a note be 
added to the effect that maceration of the ingredients should take place at a tem¬ 
perature not exceeding 70° ; and this is exactly the addition to the old process. 
Liquores. — Liquor Antimonii Terchloridi is misplaced here. Being an ar¬ 
ticle employed in a chemical process, but not itself used in medical practice, it 
should, according to the rule laid down in the Preface of the British Pharmaco¬ 
poeia (p. xi), have been placed in Appendix A., and not among the Preparations 
and Compounds. 
Liquor Arsenicalis. This is the Edinburgh and Dublin name for the London 
Liquor Potassce Arsenitis. Bell showed (Pharm. Journ. vol. xviii. p. 489) how 
objectionable the latter name was, especially in its contractions, and advocated 
a return to the old one now adopted. 
Liquor Arsenici Chloridi of the London is omitted from the British Pharma¬ 
copoeia. This is satisfactory, both pharmaceutically and therapeutically, for the 
name was wrong, and the solution itself merely a second arsenical one, and 
therefore superfluous. These objections to it were urged by Hanbury and 
Garrod (Pharm. Journ. vol. xvi. p. 542). 
Liquor Calcis Saccharatus is a solution of lime about twelve times the strength 
of lime-water. According to Peligot’s table of the composition of solutions of 
lime in syrup (Pharm. Journ. vol. xi. p. 34), it appears that the density of a 
ten per cent, solution of sugar in w-ater is 1-036 ; and that when such a solution 
is saturated with lime, its density is 1-053. The specific gravity of Liquor Calcis 
Saccharatus is 1-052 ; it is a saturated solution of lime in a 9-1 per cent, solution 
of sugar, and its strength, as determined by the volumetric solution of oxalic 
acid, is pretty much what we should expect it to be from Peligot’s researches. 
