38 



Only a f iw cuttings of each variety were introduced, and these were 

 planted only about a foot apart in nursery beds, with a view to subse- 

 quent propagation on a large scale. I now have cuttings enough to plant 

 about two acres. I regret I have been unable to establish experimental 

 plots of each variety with a view to test their respective productive capa- 

 city on the hot plains. Some of the varieties succeed best on the hills. 



The result of the analyses of the 17 varieties is important. The leading 

 variety contains the extraordinary percentage of 36-50 of starch. Other 

 varieties closely approximate to this. 



From plants systematically cultivated in the field here and planted con- 

 temporaneously with the Colombian varieties the return which I have ob- 

 tained is only 17 per cent. Doubtless by chemical analysis the yield would 

 be somewhat higher. 



From the point of view of human and animal food the analysis is also 

 extremely important. As is stated by Mr. Cousins the poisonous bitter 

 cassava o-rown in Trinidad contains 0.022 per cent of hydrocyanic acid, 

 and the sweet 0.010 per cent. Thus the sweet actually contains nearly 

 half of the hydrocyanic acid of the bitter. The contrast in this respect 

 with the Colombian varieties is remarkable. Mr. Cousins says : — " The 

 averao-e obtained for these Colombian varieties is only 0.0017 or only |- 

 the amount contained in Trinidad Sweet Cassava." 



The general result is that the Colombian varieties are par excellence 

 the varieties to be cultivated for animal food, as well as for starch 

 production. 



A New Method of Treating Cereal Grains and 



Starchy Products. 



By Dr. A. P. Anderson. 



The cereal graius including wheat, rice, barley, oats maize, and rye form 

 a most important part of the food of the human race. The chief value of 

 the cereal lies in the starch which they contain, which may amount to as 

 much as 5'-' to bO per cent of the weight of the dried kernels. 



Starch occurs in plants in the form of globose, ovoid and oblong 

 bodies of rounded outlines, the exact shape assumed in any plant being, 

 more or less characteristic of the species. Almost any growing green 

 plant will be found to contain starch grains in all stages of formation 

 from the most minute to the maximum size. Those of the potato often 

 attain a diameter of a hundredth of an inch being visible to the naked 

 eve An examination of the granules with a maguification of a few 

 hundred diameters shows that they are constructed of concentric layers 

 or coats of alternating denser and watery layers, the centrum around which 

 the layers are arranged being of the latter character. The granule con- 

 tains from 15 to 22 per cent, of water when in an air-dry condition. In- 

 vestigation of these interesting bodies with reference to their formation 

 shows that they are really bailt up like crystals,, being in fact sphaero- 

 crystals. 



Starch granules when intact are acted upon but slowly by chemicals 

 especially the digestive enzymes. Consequently starchy substances are 

 made more suitable for food by cooking or some method of treatment 

 by which the granules are broken up. When starch granules are warmed 

 in water they begin to swell at a temperature of 55° to Q>*)° C, and burst at 

 75° to 80° C, being converted into a uniformly translucent mass known 

 as starch paste in which the minute particles are suspended in the water, 

 ,but are not dissolved. 



