208 POWDERED VEGETABLE DRUGS 



M. Rumphii Mart., Sagus farinifera Lam., Arenga sacharifera Lab., 

 Palmae. Also obtained from Cycas roots. 



Granules somewhat larger than those of Cassava; irregular in 

 outline; mostly compound as in Cassava, hilum excentric; stratifica- 

 tion quite distinct. (30 to 75ju.) 



11. Yam starch, Guiana arrowroot. From the tuberous roots of 

 various species of Dioscorea of the tropics. The granules are elongated 

 with the hilum at the extreme smaller end, markings distinct, broader 

 end somewhat truncate. (30 to 50ju.) 



12. Sweet potato starch, Brazilian arrowroot. From the tuberous 

 roots of Batatas edulis Chois., Convolvulaceae. Roots from tropics 

 are comparatively richer in sugar, while roots grown in temperate 

 climates are richer in starch. Hili excentric, granules bell-shaped. 

 (10 to 40/i.) 



Starches may be obtained from a variety of other plants but only 

 exceptionally in commercial quantities. Thus starch may be ob- 

 tained from the bean, the pea, the banana, from curcuma, from ginger, 

 from Batatas edulis Chois., from the roots of the arucarias, from the 

 roots of the zamias. Oat starch occasionally is found in the market. 



Upon examining the commercial products made from starch or 

 from meals rich in starch, as pearl sago, tapioca, macaroni, spaghetti, 

 etc., it will be found that some or many of the starch granules are 

 more or less heat dextrinized. Such products may also contain an 

 excess of impurities. In the Chinese and India puffed rice, the starch 

 granules are so much disintegrated by the heat explosions as to be 

 unrecognizable. This is also true of the puffed rice of the market. 

 In " grape nuts," in the so-called malted milks, and in some other 

 manufactured foods in which considerable starch and cereal is used, 

 the starch is more or less completely dextrinized and no longer gives 

 a blue reaction with iodine. 



The illustrations of the more common starches will serve to make 

 clear their microscopic characteristics. The following key is based upon 

 the microscopical examination, without the use of the micrometer 

 scale or the polarizer. 



