POWDERING VEGETABLE DRUGS 55 



kept closed so as to prevent loss of powder and also to prevent inhala- 

 tion of poisonous and irritating drugs. 1 



5. Uniform Powdering. All parts of the drug should be reduced 

 to the same degree of fineness. Typical starch-bearing parenchyma 

 is reduced to the desired degree of fineness before the more tenacious 

 tissues, as bast, trapheids, vessels, etc., begin to be finely crushed. As 

 the less resisting tissues become reduced sufficiently they should be 

 removed by means of a sieve of the desired mesh, and the remaining 

 fibrous tissues should be reduced until all will pass through the sieve. 

 With some drugs it is possible to separate the parenchymatous, medicin- 

 ally active tissues, from the fibrous and comparatively inactive tissues, 

 as with ipecac. Some pharmacopoeias recommend that this be done. 

 It is, however, a process not readily put into practice, and hence 

 is not generally carried out, even with the few drugs where such a 

 process would be practically possible. 



6. Mixing of Powders. After grinding and sifting, the powder 

 should be thoroughly mixed, in order that the comparatively active 

 and inactive particles may be uniformly distributed; otherwise one 

 portion of the powder might be more active than another portion. 

 Upon standing for some time and during shipment, the heavier par- 

 ticles become more or less separated from the lighter particles. It is, 

 therefore, necessary to thoroughly mix the powder again just before 

 a portion or all of it is to be used. 



7. Fineness of Powders. The fineness of the powder will depend 

 upon its intended use. Theoretically it may be stated that the finer 

 the powder the more rapid and complete will be the extraction of 

 active constituents, no matter whether the powder is intended for 

 internal use, for alcoholic extraction, or for aqueous extraction. The 

 active constituents occur in the cell-lumen and in the cell- walls; the 

 individual cell should, therefore, be broken that the extractive sub- 

 stance, whether it be the saliva, gastric juice, alcohol, water or other 

 menstrua, may permeate the cell-wall and occupy the cell-lumen and 

 take up (by solution and osmosis) the medicinal principles. Theoret- 

 ically, therefore, all cells, whether long, tabular or isodiametric, should 

 be separated from each other and each cell should be broken in two. 

 This would imply that the various drugs should be reduced to very fine 

 powders. Such a condition exists practically in so-called meals, as 

 flour, almond meal, insect powder and most powders intended for 

 internal use. Upon making a microscopic examination of 'powders 

 designated as No. 80 and No. 100, it will be found that cell groups still 



1 In powdering as well as sifting irritating and poisonous drugs, eyes, nose and 

 mouth should be protected by means of a cloth or sponge. 



