CHAPTER VII 



THE MICROSCOPICAL EXAMINATION OF POWDERED 

 VEGETABLE DRUGS 



I. EQUIPMENT AND METHOD 



The ability to identify powdered vegetable drugs and their adulter- 

 ants will depend largely upon the intelligent use of a good compound 

 microscope and the necessary accessories and reagents. It is further 

 evident that the study of the histology of crude drugs is a necessary 

 preparation to the study of these drugs in the powdered state. In 

 the powders the cells and cell-contents appear broken and intermingled. 

 This fragmentary state of tissue elements renders their identification 

 more difficult as compared with these elements as they appear in care- 

 fully prepared sections of crude drugs. 



As already indicated, the fineness of the powders varies greatly. 

 For examination under a compound microscope Nos. 60 to 100 are 

 most suitable. No. 80 is, perhaps, the fineness best suited in the 

 great majority of cases. A No. 100 is generally too fine and a No. 60 

 is somewhat coarse. Very coarse powders must be further reduced 

 by means of a pestle- and mortar. For low powder examinations 

 powders from 40 to 60 fineness are very suitable. 



The equipment and apparatus required by the micro-analyst is 

 comparatively inexpensive, yet it is very earnestly advised to secure 

 only those appliances which are useful or essential for the work in 

 hand. The following list is submitted without entering into detail, 

 as it may be assumed that the microscopist does not require detailed 

 explanations: 



1. Simple lens. 



2. Compound microscope. 



(a) Ocular with micrometer scale. 



(6) Oculars, Nos. 2 and 4. 



(c) Objectives, Nos. 3, 5 and 7. 



3. Slides and covers. 



4. Section knife or razor, and strop. Safety razor blades may be used. 



5. Polarizer, for the study of starches, crystals and other substances. 

 Should be convenient to use. The selenite plates are useful. 



6. Accurate metal or hard rubber millimeter ruler for measuring crude drugs, 

 fruits, seeds, etc. 



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