1U 



With the starch in the analysis given above is reckoned also the solu- 

 ble carbohydrates, consisting almost exclusively of cane sugar, and of 

 which, in an analysis of another portion of the dry substance, as high 

 as 17 per cent were found. In the laboratory it is not difficult to pre- 

 pare crystallized cane sugar from the aqueous extract of the fresh pulp. 

 We have made such a preparation. The percentage of sugar in the 

 plant, however, is too low to excite any reasonable hope of the preparation 

 of this- article on a commercial scale. The most promising way to save 

 it is by conversion into glucose, as indicated in another place. The 

 undetermined portion consists of the digestible fiber and carbohydrates 

 of the pentose series. The pentosans in the fiber were determined by 

 the furfurol process, as modified by Krug, and the amount in the air- 

 dried material was found to be 3.92 per cent, and in the material after 

 the removal of the starch 5.33 per cent. 



The fresh root was found to contain 38.7 per cent of dry matter, being 

 considerably more than was found in the fresh sample of the previous 

 analysis. Of this 38.7 per cent, 30.98 consisted of starch and soluble 

 carbohydrates. 



Experiments were made to determine the yield of air-dry starch which 

 could be obtained from the roots by laboratory work. Two sets of 

 experiments were made. In the first set the roots were pulped on a 

 Pellet rasp, used for preparing beet pulp for instantaneous diffusion. 

 Twelve kilos of the unpeeled root were rasped in this way and the starch 

 separated by washing through a sieve of bolting cloth. The washings 

 and settlings were coll ected and dried in the ordinary method of starch 

 manufacture. The yield of pure starch was 3,105 grams, equivalent to 

 25.9 per cent of the total weight of the root. The starch was almost 

 absolutely pure, containing only a trace of nitrogenous matter. In the 

 second experiment 10 kilos of the root were ground in a pulping machine, 

 used for preparing green fodder for analysis. The pulp was much less 

 fine than that produced by the Pellet rasp. Treated in the same way, 

 the yield of air-dry starch was 2,300 grams, or 23.0 per cent. One of the 

 striking points in connection with the work is that the residue from the 

 starch, which consisted largely of fiber, as will be seen by reference to 

 the above analysis, contained still a large percentage of starch, show- 

 ing that by the process employed the whole of the starch was not 

 secured from the pulp. The diameter of the starch granules is a little 

 over 0.01 rnm., being about seven times smaller than the average of 

 potato starch. 



COMPARISON OF CASSAVA STARCH AND INDIAN CORN STARCH. 



The illustrations given are from photomicrographs of the starch 

 granules, which, .for purposes of comparison, are accompanied by illus- 

 trations of the finest prepared Indian-corn starch. 



Fig. 1, Plate I, shows the granules of cassava starch in plain light, 

 magnified 150 diameters. 



