POWDERED DRUGS AND FOODS. 697 



as the following : ( i ) If the particles sink or float. In all gen- 

 uine coffee, for instance, the particles rise to the surface, whereas 

 in the substitutes and adulterants they sink. (2) If the particles 

 disintegrate. All artificial products, as coffee and nutmeg, when 

 made from exhausted powders or spurious substances, slowly 

 disintegrate, leaving a fine sediment. (3) The color of the solu- 

 tion. A chelidonium powder, for instance, gives a golden-yellow 

 solution, as also do many drugs containing berberine and allied 

 principles. (4) Behavior of the solution and particles toward 

 alkalies or dilute hydrochloric acid. Drugs containing oxy- 

 methyl-anthraquinone derivatives, as senna, rhubarb, aloes, fran- 

 gula and cascara sagrada, are colored a deep red with alkalies. 

 The particles of ruellia give a distinct effervescence with hydro- 

 chloric acid particularly if the mixture is slightly heated. The 

 presence or absence of starch may be determined by heating the 

 mixture, to which has been added a few drops of dilute hydro- 

 chloric acid, filtering, and adding iodine to the filtrate when cool. 

 (5) The odor of the mixture, particularly on warming, is of con- 

 siderable value, as in the detection of belladonna in inula or of 

 conium in anise. The odor is also of value in recognizing the 

 specimen, as very many drugs have a characteristic odor. The 

 odor of a specimen is sometimes, however, misleading, as a num- 

 ber of substances not at all related may have a similar odor. The 

 odor of elm bark, for instance, is possessed by other substances, 

 as fenugreek and wheat middlings, particularly if these substances 

 are kept in a closed vessel. 



The fixed oil which occurs in considerable quantity in many 

 seeds interferes with their microscopical examination, and it is 

 necessary to remove this before making mounts of the material. 

 This can be accomplished by treating the powder with chloro- 

 form, xylol, acetone, ether, or other similar solvents. Alcohol as 

 a rule is not a good solvent for these oils. The solvent may be 

 added directly to the mount and the solution absorbed by means 

 of filter paper. The following drugs and foods contain fixed oil 

 and should be treated in this way : Almond, anisum, cacao, carda- 

 mom, carum, conium, coriandrum, cubeba, ergota, linum, macis, 

 myristica, pimenta, pepo, piper, sinapis alba, sinapis nigra, staphis- 

 agria, strophanthus, and the various cereal products. 



