VEGETABLE POWDERS. 



In 1893 one of us (E. Collin) published a little work entitled 

 ' Guide Pratique pour la Determination des Poudres Officinales,' in 

 which an attempt was made to reproduce those elements of officinal 

 powders that are characteristic and serve as means of identification. 

 It was intended for the use of students of pharmacy, but ihe low 

 scale upon which the drawings were made and the manner in which 

 they were reproduced left much tD be desired. 



Finally, Kocli is now publishing, under the title of ' Die Mikro- 

 skopische Analyse der Droguenpulver,' an atlas which will certainly 

 Be the most complete on the subject. Unfortunately, the high 

 price at which it is issued places it beyond the reach of pharma- 

 ceutical students. 



This was the principal reason that induced us to accept the 

 invitation of the Editor of the Pharmaceutical Journal to publish 

 a series of articles on the vegetable powders. We do not propose 

 to write an elaborate treatise on the analysis of vegetable powders, 

 but simply to describe and illustrate those elements that are 

 characteristic of officinal powders, and thus to place within the 

 reach of pharmaceutical students a series of studies and drawings 

 that will enable them to identify the vegetable powders used in 

 their profession. 



The methods that are used for preparing these powders for 

 microscopical examination are very simple. For starches it is 

 sufficient to take a little from various parts of the specimen, so 

 as to be sure of having an average sample, mix these in a watch 

 glass and add a little dilute glycerin, stirring well with a glass 

 rod. After the lapse of an hour the mixture may be again stirred, 

 a drop transferred with the rod to a slide and covered with a 

 coverslip. A simpler method still consists in transferring a little 

 of the starch to a drop of water on a slide, well mixing and 

 covering ; in this case the preparation dries rather readily, but 

 delicate markings are more clearly visible than they are in dilute 

 glycerin. In either case great care must be taken that the quantity 

 of starch is not too large in proportion to the quantity of medium 

 in which it is mounted. If on examination the grains are seen 

 to lie over one another, or even if they appear crowded, more of 

 the mounting medium should bo added or a fresh preparation 

 rfiade. 



Many starch grains exhibit a delicate concentric striation, 

 which, however, is often difficult to see ; it may be made more 

 visible by adding to the preparation one or two drops of a 2 per 

 cent, aqueous solution of chromic acid. 



In the case of flours it is often desirable to examine the struc- 

 ture of the particles of bran that it contains, as these frequently 

 furnish valuable indications. This may be done by making a 

 fresh preparation to which one or two drops of glacial acetic acid 

 are. added. The coverslip is dropped on and the slide warmed until 



