364 PLANTS AND MAN 



readily upon exposure to air, after which it is cleaned and 

 molded into cakes. Bdlata rubber is used for machine beltings — 

 since it grips tightly and does not stretch; as a substitute for 

 chicle in the manufacture of chewing gum; and for insulation, 

 pipe stems, golf balls, and adhesives. 



Chicle, a gum produced by the sapodilla or naseberry, also 

 of the Soapberry Family, is the basis of the chewing-gum indus- 

 try. The tree — a fine, tall hardwood with evergreen leaves — is 

 indigenous to Mexico and Central America, but is cultivated 

 elsewhere in tropical America and Florida for its edible fruit. 

 The latex is obtained by tapping the tree with zig-zag gashes 

 up to a height of thirty to fifty feet, and directing the latex 

 flow to a cup or hollow in the earth at the base of the tree. The 

 flow of latex lasts for several hours, but the trees can be tapped 

 only at intervals of two or three years, hence plantations of the 

 species, though being started on a limited scale are not very 

 practicable. The chicle is collected and taken to a central camp 

 where it is boiled and molded into blocks for shipment. 



Chicle has been chewed locally for hundreds of years, but its 

 manufacture into a chewing-gum was not practiced until some 

 time late in the nineteenth century. From a crude beginning 

 about seventy years ago, the United States chewing-gum indus- 

 try has grown until it imports almost $5,000,000 worth of raw 

 chicle annually, which is almost the entire output of this product. ^J 

 Upon reaching the manufacturer the blocks of chicle are broken 

 up and purified by washing with chemicals, after which processes 

 of sterilization, compounding with sugar and flavoring materials, 

 and cutting, wrapping, and packaging are all carried out by 

 machinery. 



African Latex-producing Plants 



The number of latex-yielding plants in Africa is considerable, 

 but in spite of this the future outlook for rubber production in 

 Africa is very dark, the most valuable rubber-producing Africans 

 trees and shrubs having been practically exterminated by the] 

 barbarous methods used in collection of the latex, not to mention^ 

 the human savagery resorted to by some countries in the exploi-- 



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