POWDERED DRUGS 711 



author 1 prefers the latter method, and the following key, involving 

 the examination of nearly 300 different substances, will be found 

 helpful in practice and render expeditious the examination of even 

 complex mixtures. A complete microscopical description of each of 

 the powdered drugs, has already been given throughout the text, 

 and these descriptions, as also the statements under inner structure, 

 should be referred to by the analyst. It is very important when 

 possible to compare the specimen under examination with authentic 

 material. It will be found convenient to arrange all drugs having a 

 similar color upon a single card, which can be filed away in suitable 

 compartments, and at the same time easily accessible when needed 

 for comparison. 



Adulterants. Powdered drugs are frequently adulterated either 

 by the use of wheat middlings or with exhausted powders, i.e., those 

 from which the active or important constituents have been extracted. 

 The following examples serve to illustrate the methods in use: 

 Powdered cloves are occasionally admixed with the exhausted 

 powder, or the exhausted powder alone to which a small quantity 

 of oil of cloves and some coloring matter are added, is sold as pow- 

 dered cloves. Exhasuted gentian, to which has been added a small 

 quantity of a bitter drug like aloes, is sold in place of the genuine 

 drug. In some cases, as in that of ground flaxseed, an attempt is 

 made to supply the deficiency in oil of the exhausted product by 

 adding a petroleum oil. In tho case of a number of drugs, such as 

 rhubarb, licorice and belladonna root, much of the commercial pow- 

 der consists, in part at least, of the exhausted powder. In order to 

 guard against the use of exhausted drugs there is a disposition to lay 

 considerable stress upon the amount of extractive (aqueous, alcoholic 

 or ethereal) yielded by different drugs. In many instances drugs 

 that are worm-eaten, or admixed with other drugs or plant parts, 

 are used in the preparation of powdered drugs. 



Reagents. For the rapid differentiation and study of the char- 

 acteristic tissues and cell-contents of the powder it is necessary to 

 employ reagents which render the particles more or less transparent 

 and at the same time do not destroy their characters. The most 

 satisfactory reagent of this kind for general purposes is an aqueous 

 solution of chloral or a solution of chloral and glycerin; about a 

 milligram of the powder is mounted in a few drops of the solution, 

 the preparation is gently heated, then allowed to cool, and examined; 

 if it is not sufficiently transparent, it is heated again. The reagent 

 causes a swelling of the cell-wall and is not applicable in the study of 

 1 Kraemer, Amer. Jour. Pharm., 1898, pp. 506, 558, and 6Q7. 



