xvi INTRODUCTORY 



as aging, lack of care in preparation, substitution, extraction of 

 important constituents, or the addition of other substances which 

 may be either harmless or harmful. Adulteration may occur in a 

 great variety of forms. The following may be mentioned as giving 

 some idea of not unusual occurrence: 



Large pieces of iron may be used to increase weight, as in Bur- 

 gundy Pitch ; pieces of lead pipe may be inserted in the fresh root as 

 in Ginseng; bullets are occasionally found in the masses of opium; 

 pebbles and rocks admixed with asafcetida; large quantities of dirt 

 may be left in the middle of the bundles of sarsaparilla ; the substi- 

 tution for a proximate principle, as papain by bread; admixture or 

 even substitution by other species as apocynum, hyoscyamus and 

 scammony, in which occur closely related forms; the substitution 

 by widely separated genera as Mountain maple bark for Viburnum 

 Opulus; in still other cases toxic drugs may be substituted for the 

 genuine, as spurious cubebs for true cubebs, belladonna for inula. 



Micro-chemistry. During the past fifteen or twenty years there 

 has been a growing interest in the study of plant constituents by 

 the application of chemical reagents to microscopic sections. 



Up until recently we have been largely concerned in the identi- 

 fication of raw materials and have been quite content to be able to 

 distinguish the genuine article from spurious substances. This 

 work has been based largely upon the forms of cells and composi- 

 tion and structure of the cell wall. In some instances the study 

 of some of the cell contents, as of starch grains and crystals of cal- 

 cium oxalate, has afforded an important clue to the identity of the 

 product under examination. As our interest in the study of the 

 quality of the drugs increases, and this is based upon the constituents 

 or those principles called active principles, it is very important that 

 these constituents be studied in the cells of the plants and drugs. 



A careful perusal of the literature will show that very many 

 observations have been made showing the separation out in micro- 

 scopic sections of definite crystalline substances. In some cases 

 these occur even upon the outside of the drug, as the coumarin crys- 

 tals on tonka beans and vanillin crystals on vanilla pods. 

 Again, these crystals may be formed upon heating the material, as in 

 benzoin and many other drugs. 1 Again, crystalline substances 

 separate upon the addition of mineral acids, as when nitric or sul- 

 phuric acid is added to sections of hydrastis. Cognizance of these 

 crystals is being taken to some extent in all of the progressive phar- 

 macopoeias, and while the subject is in a more or less chaotic condi- 



J Otto Tunmann, "Pflanzenmikrochemie," 1913; Kraemer's "Applied and 

 Economic Botany," 1916. 



