STARCH AND SUGAR. 



275 



very much alike, but readily distinguishable after very many 

 grains are measured. The size of each kind is as follows : 



248. Potato Starch, from tubers of /Sfe^anMmiwJerosMm. 

 (family Solanacece), is distinguishable from wheat starch by 

 the naked eye. The grains are 

 so large that they are recognized 

 as such even without the aid of 

 a lens. The paste made from it 

 is not so stiff nor so viscid as 

 that made from wheat starch ; 

 it has also an unpleasant smell. 

 The grains are mostly, but not 

 always, simple, large and oval, and the layers are very 

 distinct (Fig. 348). The nucleus is near the narrow end ; 

 the eccentricity varies from one-fourth to one-sixth. 



249. Rice Starch, from Oryza sativa (family Gror 

 minece), often has a yellowish color, but sometimes (the 

 finest) is dazzling white. It is often bleached with chlo- 

 rine compounds. It appears to the unaided eye like wheat 

 starch ; but with the simple lens no grains are visible. 

 The grains are (1) single, and of the same size as the 

 partial grains; and (2) compound, which are oval and 

 consist of 2-100 parts. Instead of a nucleus, they have 



Fig, 348. Starch grains from the Potato. 



