VEGETABLE POWDERS. 



The microscope has long been used for the examination of the 

 various starches and flours, but it is only within recent years 

 that this method has been adopted for the identification of officinal 

 powders. This advance had its origin in the recognition of the 

 fact that external characters are not invariably reliable indication* 

 of identity, and that other more constant ones must be sought 

 for in the anatomical structure ; the change that has taken place 

 in the conditions under which the profession of pharmacy is car- 

 ried on has rendered such advance necessary. 



The utilisation of the anatomical structure of a drug as a guide 

 to its identification dates from 1847, when Schleiden, in his 

 classical work on the sarsaparillas, showed that it was possible 

 by this means to distinguish the commercial varieties from one 

 another. Weddell in 1849, Howard in 1862, and others confined 

 themselves to the examination of cinchona bark, but Oudemanns 

 in 1854-56 published in his Commentary to the Dutch Pharma 

 copoaia illustrations of the anatomy of official vegetable drugs. 



In 1865 Berg's classical anatomical atlas appeared, and systematic 

 work was more generally undertaken, as for instance in France 

 by Planchon. These different authors, however, restricted them- 

 selves to describing the structure of the drugs and made no attempt 

 to deal with their powders. The first to break ground in this 

 direction was Vogl, and he was quickly followed by others. 

 Tschirch contributed, in his ' Angewandte Pflanzenanatomie,' a 

 number of valuable observations, which he has completed in his 

 superb anatomical atlas. The latter work was the first to present 

 a systematic account of the diverse appearance of the various 

 anatomical elements in transverse, longitudinal, and surface section 

 The latter is especially valuable, as it is the aspect presented 

 by the different elements in the powdered drug. 



The first work that dealt specially with vegetable powders- 

 was Moeller's ' Pharmacognostischer Atlas,' in which, however, to 

 a great extent large fragments or sections of the drug w?re 

 represented rather than the elements as they occur in powders. 

 At the same time Herlant produced in Brussels a work on 

 officinal powders, in which he endeavoured to reproduce by photo- 

 graphy the appearance of the principal powders used, in pharmacy. 

 It has, however, always appeared to us that a good drawing is 

 to be preferred to a photograph. By the latter method starch, 

 if present in quantity, may conceal important tissues, and at least 

 two photographs would have to be made. Moreover, it must 

 always be remembered that a drawing made to illustrate a vege- 

 table powder consists of characteristic elements and tissues that 

 have been selected from various parts of one slide, or even from 

 several slides ; they seldom or never occur in the field of the 

 microscope at one and the same time, and therefore do not lend 

 themselves to any mechanical method of reproduction. 



Braemer and Suis have also published a work dealing with the 

 Iwives and illustrated in a similar way. 



