This section is from the book "The Wonder Book Of Knowledge", by Henry Chase. Also available from Amazon: Wonder Book of Knowledge.
Crude rubber is received in many forms under various names. There are more than three hundred standard kinds, depending on source and method of handling; e. g., "Sernamby" is simply bundles of Para tree scrap and scrap from the cups where milk has cured in the open air. "Guayule" is a resinous rubber secured from a two-foot shrub that grows on the arid plains of Texas and Northern Mexico.
Our picture shows a bin of crude up-river Para the finest rubber known. Every "biscuit" or "ham" has been cut in two to find out whether the native has loaded it in any way.
 
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