4Q8 POWDERED DRUGS 



During the process of pulverization the less resisting tissues, such as 

 thin-walled parenchyma cells, which, for the most part, contain starch, 

 proteids and crystals, are reduced rapidly to powder, while the woody and 

 fibrous parts together with the tracheids and vessels are quite difficult 

 to pulverize. Accordingly, frequent sifting should be resorted to during 

 the process, so that as the broken fragments are reduced to the proper 

 size to pass through the sieve they may be removed. The process of 

 grinding and sifting must be continued until all the tissues have passed 

 through the sieve. Powders in small quantities may be made by means 

 of a mortar and pestle, and if the material is thoroughly dry the time and 

 labor need not be great. A mortar and pestle made rough" by the use of 

 coarse carborundum powder has proved very efficient. Coarse powders 

 in considerable quantity may be made in an ordinary small coffee mill. 

 The process of grinding may then be continued by means of mortar and 

 pestle and the fineness carried to any degree desired. 



Color. Vegetable powders are liable to vary greatly in color. Some 

 of the common factors which cause this variation are light, moisture and 

 increasing fineness. Exposure to light deadens the color, in some cases 

 very rapidly, a light or reddish-brown soon becomirig a dark or dull brown, 

 etc. By exposure to moisture most powders grow dark in color. In- 

 creasing fineness produces varying tints and, in some instances, the quality 

 of the color is wholly changed; for example, Spanish Licorice, in coarse 

 powder, is yellow showing considerable portions of brown cork, while a 

 very fine powder is almost lemon color. If the process be carried on by 

 alternate grinding and sifting, as described above, tints from yellow to 

 light lemon yellow will be obtained. The aging of powders, even when 

 not exposed to light, changes them to darker tints. Powders made from 

 plant parts, rich in oil, are likely to be dark in color and the darkening may 

 become marked if heating is allowed to occur during the grinding. They 

 darken rapidly on exposure to light and are likely to become rancid. 



Various systems of classification by colors have been worked out for 

 the vegetable drugs. Doctor Schneider has divided them into six groups 

 as follows: i, Very light; 2, yellow; 3, green; 4, gray; 5, brown; 6, very 

 dark. Professor Henry Kraemer forms them into five main groups: i, 

 Greenish powders; 2, yellowish powders; 3, brownish powders; 4, reddish 

 powders; 5, whitish powders. These groups are subdivided according to 

 the forms of cells, nature of the cell wall and cell products. All such 

 systems as these are more or less artificial, and although useful in many 

 cases, have not proved wholly satisfactory in the laboratory. 



Identification by Odor. The odors from drugs are exceedingly diffi- 

 cult to describe, largely because we have no odor standards at command 

 for comparing them qualitatively or quantitatively. We can understand 

 such terms as aromatic, pungent, fragrant, agreeable, disagreeable, etc. 

 These terms serve in a measure to indicate odor qualities. 



