BRITISH PHARMACEUTICAL CONFERENCE, EXETER. 425 



The British Pharmacopoeia has recognised the value of such 1869. 

 medicines, and has given formula? for the preserved juices of p re served 

 scoparium and of conium, both excellent preparations, the juices, B. P. 

 latter especially being superior to any tincture prepared from a 

 dry ingredient, whether leaf or fruit. It has been reserved, how- 

 ever, for a Belgian apothecary to investigate the subject in a 

 thoroughly scientific manner, and to point out in what way and to 

 what extent, the dried medicinal plant differs from the fresh. The 

 late Dr. Schoonbroodt of Liege has done this, and has published 

 in the Journal de Mtdecine de Bruxelles l the result of his re- 

 searches on twenty-nine different plants, concluding his essay with 

 some general remarks, of which I may cite the following : 



That dried plants never completely represent the same plants Dried plants, 

 when fresh. Nevertheless it is possible for new and useful con- 

 stituents to be developed during the process of drying, as in the 

 case of valerian, which when fresh contains essential oil but no 

 valerianic acid; this, however, is an exceptional instance, the 

 reverse being much more frequent. 



That plants suffer by drying two kinds of alteration ; firstly, Alteration by 

 the loss of a portion of their volatile constituents ; and 

 secondly, an oxidation of their fixed constituents and of the 

 remainder of their volatile. This oxidation is, in the author's 

 opinion, in great part due to the structure of the dry vegetable 

 tissue, which in its porosity resembles spongy platinum or 

 carbon, and perhaps partakes of some of the gas-condensing 

 power of those substances. The result of this action exhibits 

 itself very decidedly in the case of valerian: when fresh, it 

 contains no valerianic acid but an , oxygenated essential oil, 

 which by the action of the air and alkalies, is slowly converted 

 into valerianic acid. It also contains another volatile hydro- 

 carbon, which resinifies very slowly in the air. By the act of 

 drying however, this formation of valerianic acid which even in 

 the presence of an alkali is so slow, and this very tardy resini- 

 fication by exposure to the air, are very materially hastened. 



1 Vol. 45 (1867) p. 162 etc. ; vol. 46, (1868) p. 62. A German translation 

 has appeared in the Vierteljahresschriftf. PraJct. Pharm. 1869, p. 73, and an 

 abstract by Mr. Maisch in the American Journ. of Pharm. and Pharm. 

 Journ. and Trans. 



