156 POWDERED VEGETABLE DRUGS 



In order to be able to select an average or representative sample 

 of the commercial article, considerable experience is necessary. Spice 

 dealers are, as a rule, excellent judges of the quality of the products to 

 which they have given years of close observation. The wholesale 

 drug dealers are thoroughly familiar with the appearance of the crude 

 drugs as they are offered on the market. Grain merchants can, at a 

 glance, determine the grades of the various cereals. Tea experts 

 will recognize aromas and flavors entirely lost to the inexperienced 

 observer. Fortunately, it is not expert ability which is required to 

 select a representative sample, but rather a familiarity with a fair 

 quality or grade of the articles to be examined. If, for example, it is 

 desired to examine ground black pepper as to the approximate percent- 

 age of pepper hulls present, the comparison is to be made with a fair 

 quality of whole black pepper, not with so-called " grinding peppers, " 

 or peppers otherwise defective, or with some special commercial 

 variety or blend of black pepper. Before grinding, all sand, dirt, pepper 

 stems, and markedly defective fruits must be removed. Considerable 

 care must be observed in selecting an average sample of a root drug 

 or of a drug composed of roots and rhizomes, or of leaves and stems. 

 It is necessary to have on hand carefully selected average samples of 

 drugs, spices, cereals, coffees, teas, cocoas, etc., inclusive of the various 

 refuse tissues and the various milling by-products, as well as articles com- 

 monly employed as adulterants, such as nut shells, olive pits, tea dust, 

 coconut shells, screenings and tailings, refuse and trimmings, colocynth 

 seeds and rind, corn cobs, corn silk, bran and millings, cereal chaff, wild 

 mace, wild nutmeg, chicory, male fern chaff, tobacco stems, senna stems, 

 senna siftings, roots ofRuellia ciliosa, false senega, pokeroot, etc., etc. 



2. Grinding or Powdering the Sample. After the average sample 

 has been garbled, cleaned and thoroughly dried, it is reduced to a No. 

 80 powder, inclusive of all tissues which may be present. 



In some instances it will be found necessary to reduce the material 

 to be examined and compared to a much greater fineness, in a special 

 mill or a mortar. In order to make accurate starch counting pos- 

 sible the starch bearing tissue must be made sufficiently fine to pass 

 through a 200 mesh sieve or through bolting cloth. In other in- 

 stances certain tissues may be removed and separated in comparative 

 purity by means of very coarse mesh sieves (Nos. 8, 20, 40). In this 

 manner such substances as bran, crude fiber, coarser meals, shells, 

 etc., may be separated from the finer elements and their percentage 

 values determined separately, as will be explained. 



3. Mixing the Powdered Sample.- After the grinding, the entire 

 amount must be thoroughly mixed by means of a spatula. Shaking 



