698 BOTANY AND PHARMACOGNOSY. 



All powders contain a certain amount of fragments of cell 

 walls and other materials which are more or less alike in the dif- 

 ferent powders, and it is important that this fact be borne in 

 mind in order that attention may be especially directed to those 

 elements of the powder which have a diagnostic value. The latter 

 while relatively few in number, are easily identified and the dis- 

 tinguishing features readily determined in nearly all cases. 



Inasmuch as the size and shape of starch grains and calcium 

 oxalate crystals are characteristic for very many drugs, classifica- 

 tions of these based on the foregoing characters are given before 

 taking up the study of the individual powders. 



A. DRUGS AND FOODS CONTAINING STARCH. 



The more important vegetable drugs, including some of the 

 commercial starches, are here grouped according to the size and 

 shape, or other characters, of the starch grains : 



SIMPLE SPHERICAL GRAINS. 



Not more than 5 M in diameter : Cimicifuga, cypripedium, frangula 

 (Fig. 228), Hydrastis (Fig. 292), leptandra, piper (Fig. 311), prunus 

 virginiana, quassia (Fig. 239), quercus alba, rhamnus purshiana (Figs. 

 229a, 304), spigelia, viburnum opulus and viburnum prunifolium. 



Not more than 10 M in diameter: Calamus (Fig. loi, B), euonymus, 

 gelsemium (Fig. 208), granatum (Fig. 234), quillaja (Figs. 281, C; 315). 

 sanguinaria, serpentaria, tonka, ulmus, xanthoxylum. 



Not more than 15 fJ- in diameter: Apocynum (Fig. 202), cinchona 

 (Figs. 227, 307, 307a), colchici semen (in caruncle only), convallaria, 

 sumbul, Valeriana. 



Not more than 20 m in diameter: Glycyrrhiza (Figs. 104; 2%2,B ; 

 204), Phytolacca. 



Not more than 30 m in diameter: Rumex, stillingia. 



COMPOUND SPHERICAL OR POLYGONAL GRAINS. 



Two- to three-compound: Belladonnse radix, 5 to 15 /^ (Figs. 200; 

 281, D; 303) ; sassafras, 7 to 20 /^ (Fig. 236) ; and veratrum viride, 7 to 

 20 M (Figs. 215, 216). 



Two- TO four-compound: Aconitum, 4 to 12 m (Figs. 206, 309); 

 cinnamomum, 7 to 15 M (Figs. 224, 225, 305) ; colchici cormus, 7 to 20 m; 



