68 



The World's Commercial Products 



Photo bv W. G. Freeman 



THE BREAD-FRUIT 



Large 'quantities of dex- 

 trin or British gum are manu- 

 factured in Europe from 

 potato starch. The starch 

 is subjected to a high tem- 

 perature, preferably in con- 

 tact with the diluted vapours 

 of nitric acid. 



CASSAVA STARCH 

 AND TAPIOCA 



Cassava, manioc, or man- 

 diocca, is the starch prepared 

 from the roots of two species 

 of Manihot. The plants, 

 which are natives of tropical 

 America, are very closely re- 

 lated, and are often regarded 

 merely as varieties, and not 

 as separate species. They 

 are shrubs reaching a height 

 of about six or eight feet with repeatedly forking branches, bearing palmate leaves 

 divided into from three to eleven divisions, and mounted upon slender leaf stalks. 

 The roots, which are the only valuable portions of the plant, grow in clusters often 

 weighing as much as twenty pounds or more ; the individual roots vary in length from 

 one-and-a-half to four or even six feet, and generally average about two inches in diameter. 

 Cassava is extensively cultivated in many parts of the tropics, since it is a crop which yields 

 a large return for a comparatively small amount of labour ; large quantities are grown in 

 Brazil, Guiana, the West Indies, West Africa, the East Indies, and the Straits Settlements. 



Both the " Sweet " and the " Bitter " Cassava are extensively grown, but the " bitter " is 

 more generally cultivated, as, although it requires a much longer time to reach maturity, it 

 produces a greater yield of roots. There are a dozen or more varieties of the bitter cassava 

 grown in Brazil differing principally in the colour of the stems and roots and in time of reaching 

 maturity. All of these varieties contain a considerable amount of the active poison prussic 

 acid, but fortunately the poison is very volatile and is entirely dissipated by moderate heating, 

 so that, after proper cooking, there is no danger of poisoning when eating the roots or the 

 starch prepared from them. 



In his interesting book, "Among the Indians of Guiana," Sir E. F. im Thurn gives a detailed 

 account of the methods of preparing cassava adopted by the natives, who make the product 

 into bread resembling oatcakes or use it as a kind of meal. The operations are principally 

 carried out by the women, and form a characteristic feature of Indian life. The women squat 

 upon the ground and peel the outer rind from the cassava roots with a large knife. Each 

 root after being peeled is thoroughly washed, when it is taken in hand by another woman, 

 who scrapes it vigorously up and down a rasper consisting of a short board studded with small 

 fragments of stone. One end of the rasper stands in a trough on the ground and the other rests 

 upon the woman's knees, and, as the pulp slips from the scraper into the trough it is collected 

 and put into a long narrow cylindrical bag which hangs from the roof of the hut. The bag, 

 which is known as a " matapie," is woven from strips of the pliant cuticle of the leaves of 

 the Ita palm, and its use is to squeeze the poisonous juice out of the cassava. This 

 is effected in one of two ways ; a common practice is to suspend a heavy weight from the 

 lower end of the tightly packed matapie which, as stated above, hangs from the roof, and the 



