MICROSCOPICAL DIAGNOSIS. 



8 9 



appear to be clipped, which is due to the pressure of the adjoining 

 starch grains. The nucleus is eccentric, as indicated by a dark cross 

 or slit which frequently extends the length of the grain ; the surface 

 is irregular or tuberculated-, and marked by a few distinct rings, 

 fewer than are seen in the potato-starch grain. The grains exhibit a 

 faint cross when viewed with polarized light. The starch grains 

 composing commercial sago are so changed by the process to which 

 they are subjected before being ready for market, that there is little 

 resemblance between them and the fresh grains. The starch grains 

 found in the pearl sago are the most changed by heating. Sago is 



^4 r - 36- Buckwheat Starch. 

 not used so much in this country for an adulterant as in Europe. 

 Commercial sago is frequently adulterated with potato starch, some- 

 times with rice. Sometimes there is an entire substitution of pota- 

 to starch for the sago. Any adulteration used for sago can readily 

 be detected by the microscope, by noticing the above described 

 characteristics. 



Tapioca Starch is" prepared from manioc or cassava, or, accord- 

 ing -to Linnaeus, from the root of Janipha Manihot. In the prepa- 

 ration of tapioca for market, the substance is subjected, to a tem- 

 perature of 100 degrees C., which changes the appearance of the 

 starch grains very much from what they are in their fresh state, 

 yet they are not entirely destroyed. The heat partially dissolves 

 the outer case of the starch grains, which renders tapioca slightly 

 soluble in water. The grains are quite uniform in si/c (about ., (l : 0n 



