RELATION OF THE BRITISH PHARMACOPOEIA TO PHARMACOLOGY. 567 
largely profited by the published observations of practical Pharmaceutists. In 
Decoctum Taruxaci , the difficulty or impossibility of having fresh roots always 
ready, as taken for granted by the London and Edinburgh Pharmacopoeias, is 
met by ordering the “ dried ” root to be used. This alteration was also sug¬ 
gested by Proctor (Pharm. Journ. 2nd ser. vol. i. p. 10). [Professor Bentley has 
noticed that Decoction Ulmi , though alluded to under Ulmns in the Materia 
Medica of the Pharmacopoeia, has been omitted from the Preparations. In the 
small edition just published, not only is Decoctum Ulmi omitted from the Pre¬ 
parations, but in the Materia Medica also it is “ conspicuous by its absence.”] 
Digitalinum. —In addition toProfessor Bentley’s allusion (Pharm. Journ. vol. 
v. p. 481) to the overlooked researches of Homolle and Quevenne on this principle, 
attention may be drawn to those of Mayer, Englehardt, Rochleder, and others 
(Chem. Hews, vol. viii. pp. 64 and 76), from which it would seem that the 
Digitalis purpurea mainly owes its value to a volatile alkaloid, and that digi¬ 
talin itself is suspected to be identical with, or have a close relation to, several 
lion-nitrogenous proximate principles characteristic of the Scrophulariaceous 
plants. As a source of Digitalin, Buchner (Pharm. Journ. vol. xi. p. 419) 
says that the seeds are preferable to the leaves of the foxglove, the efficacy of 
the leaves depending (Vogt., Pharm. Journ. vol. xi. p. 523) on the season when 
they are gathered. Altogether the subject is one much needing investigation. 
It is satisfactory to see that the Royal Academy of Medicine of Belgium has re¬ 
cently offered a prize medal of 500 francs for an essay on Digitalin, including 
its clinical history, composition, distinctive characters, and a process of extraction 
which shall give a constant and definite product. The competition is to close 
on April 1st, 1865. 
Emplastra. —Haselden’s suggestion (Pharm. Journ. 2nd ser. vol. i. p. 546) 
and the directions of the Edinburgh and Dublin Colleges to include Resin in 
the formula for Emplastrum Belladonna; have been adopted; at the same time 
the London strength, which was double that of the other colleges, is retained. 
This compromise will probably result in the production of an adhesive and effi¬ 
cacious plaster. 
The process for Emplastrum. Calefaciens is new. The Cantharides is to be 
exhausted by infusion in boiling water, which, according to Beaupoil, Robiquet, 
Proctor, and others (Pharm. Journ. vol. xii. p. 291), perfectly extracts the 
active matter. The resulting plaster will possibly take the place of the Irish 
Emplastrum Calefaciens , which was a simpler preparation, and the Scotch Em¬ 
plastrum Cantharidis Composition; it contains, however, no Burgundy Pitch. 
The last two English Pharmacopoeias have not had any corresponding Warm 
Plaster. 
Emplastrum Cantharidis. In preparing this plaster, wax, suet, and lard are 
to be melted together, then mixed with melted resin, and after removing the 
source of heat and before the mixture solidifies, cantharides in fine powder are to 
be sprinkled in, the whole being briskly stirred. Row Muller, so long ago as 
1841, has shown (Pharm. Journ. vol. i. p. 502) that the uncertainty which some¬ 
times attends the effects of blistering plaster, as usually prepared, may be as¬ 
cribed to the circumstance of the vesicating principle remaining locked up in 
the tissues of the fly. In order to obtain a plaster more uniform in its operation, 
Muller recommended that the cantharides be left to digest in the piaster kept 
fluid at a moderate heat for five or six hours. Soubeiran (ibid.) considered 
Muller’s suggestion a very good one, corresponding with what Guibourt had said 
on the same subject. At about the same date Donovan demonstrated the superior 
efficacy of the plaster when the cantharides had been digested in the fats at an 
elevated temperature. Ince too (Pharm. Journ. vol. ii. p. 391), though citing a 
case in which Donovan’s instructions, strictly followed, resulted in serious injury 
to the face of the operator from the volatilizing of the cantharidin, stated that a 
