490 
LECTURES ON THE BRITISH PII ARM A C 0 T (EIA. 
indifferently used for the Confectio, Extractum Colocynthidis Compositum, and 
Mistura ; but under the head of Mistura in the Preparations we see that Scam- 
mony Resin is alone ordered. We must leave the authors of the Pharmacopoeia 
to explain this inconsistency. 
Senna Alexandrina.—Senna Indica. —It should be noticed that Alexan¬ 
drian Senna and the kind called Tinnivelly are alone officinal in the British 
Pharmacopoeia, and are directed to be used indifferently in the preparations of 
that drug. The old sort of East Indian Senna should be, therefore, no longer 
employed. Alexandrian Senna is stated to be derived from Cassia lanceolata , 
Lamarck ; and Cassia obovata , Colladon. Tinnivelly Senna is referred to Cassia 
elongata , Lemaire. 
Taraxacum. —“The fresh roots ; gathered between September and Febru¬ 
ary,” are ordered, and in the list of preparations directed to be made therefrom, 
as enumerated in the Materia Medica, we find the Decoctum, Extractum, and 
Succus. Upon turning to these separate preparations, we observe that some¬ 
what different directions are then given ; thus, for the Succus, dandelion root is 
simply ordered ; for the Extractum, fresh dandelion root; and for the Decoctum, 
dried dandelion root. We are again at a loss to understand these discrepancies 
between the Materia Medica and the Preparations and Compounds. In another 
issue of tiie British Pharmacopoeia it will not only be desirable to order dried roots 
as well as fresh in the Materia Medica, but absolutely necessary if the Decoctum 
is to be retained ; for otherwise this preparation can only be prepared according 
to the Pharmacopoeia directions at certain seasons, which would be absurd.* 
The best time for collecting Dandelion roots for use in medicine has been re¬ 
peatedly alluded to in papers published in the Pharmaceutical Journal, and the 
opinion which I have frequently publicly stated, remains unchanged ; namely, 
that the roots are most active at the end of February or beginning of March.f 
According to the directions given in the British Pharmacopoeia, Dandelion roots 
may be collected any time between September and February. It is clearly a 
mistake, however, to order them to be obtained in the winter months, as frost has 
a manifest effect upon their activity. Next to the time I have indicated, I be¬ 
lieve the best period to be from the middle of October to the middle or end of 
November. 
Tragacantha.— Tragacanth is said to be a gummy exudation from the stem 
of Astragalus verus, Olivier ; and possibly other species. On the table is a 
specimen of Astragalus gummifer , brought from Syria by Mr. Daniel Hanbury, 
and now in the Museum of the Pharmaceutical Society, on which gum tragacanth 
may be seen concreted on the surface of the stem. The tragacanth of this plant 
does not, however, appear to be found in commerce ; although there can be but 
little doubt that commercial Tragacanth is derived from more than one species 
of Astragalus ; but what those species are is, at present, doubtful. Tragacanth 
is stated in the British Pharmacopoeia to be a gummy exudation from the stem ; 
but the best flaky Tragacanth is not a spontaneous exudation, as would be in¬ 
ferred from the Pharmacopoeia, but the gum which flows from the stem after 
incision, as any one may convince himself by examining the fine specimen of 
flaky Tragacanth in situ which is upon the table. X 
Ulmus. —“ The dried inner bark , deprived of its outer layers; from trees in¬ 
digenous to, and cultivated in Britain,” is ordered in the Pharmacopoeia. We 
presume that the bark deprived of its outer layers is intended, and that the -whole 
of the inner bark should be used. 
Only one preparation of Elm Bark is mentioned in the Materia Medica, 
namely, the Decoctum; but no such preparation, or any other, so far as we can 
* Prof. Bentley, “ On the Characters of Dandelion Boot,” Pliarm. Journ. vol. xvi. p. 304. 
f Pliarm. Journ. vol. xiv. p. 260, and vol. i. 2nd ser. p. 402. 
X Journ. de Pliarm. et de Cliimie, Feb. 1856, p. 117, and Feb. 1857, p. 149; Pliarm. Journ. 
vol. xv. p. 18. 
