RUBBER 



PLANTATIONS IN MEXICO AND 

 CENTRAL AMERICA 



NEXT to coffee and sugar, crude 

 rubber is the largest of the 

 tropical imports of the United 

 States. It is the only one of these three 

 for which we are entirely dependent on 

 foreign countries. The value of the 

 crude rubber that we import every 

 year, 55,000,000 pounds, reaches about 

 $30,000,000, but none of it comes from 

 Porto Rico or the Philippines. Over 

 one-half of the total is imported direct 

 from Brazil, while considerable quanti- 

 ties come from the United Kingdom, 

 presumably the products of her colonies, 

 and from Belgium, chiefly the product 

 of the Congo Free State. 



It occurred to the Department of Agri- 

 culture, while pondering what new in- 

 dustries might be found for Porto Rico 

 and the Philippines to improve condi- 

 tions on the islands, that rubber trees 

 might be grown profitably on them. An 

 agent of the Department, Mr O. F. 

 Cook, was therefore sent to Central 

 America and Mexico, where millions of 

 dollars are invested in rubber planta- 

 tions, to study rubber culture and to 

 report on the advisability of starting 

 similar plantations in our new island 

 possessions. Mr Cook spent several 

 months at the different rubber planta- 

 tions, and his preliminary report has 

 been published by the Department. 



It is yet too soon to state definitely 

 whether rubber trees can be successfully 

 grown in Porto Rico, but the prospects 

 seem favorable for growing the Castilla 

 rubber tree, as the southwestern part of 

 the island is dry and hot. It should be 

 noted that crude rubber may come from 

 three different kinds of rubber trees, 

 each requiring different climate and 

 soil. There is the Para rubber tree 

 (Hevca), which thrives in the wet valley 

 of the Amazon, but which will not grow 

 in a dry climate ; the Assam rubber 



(F/ais elastica) of Java, also needing a 

 humid atmosphere ; and the Castilla 

 rubber tree of Central America and 

 Mexico, which prospers best where it is 

 dry and hot and will not grow in swamps 

 or wet soil. Mr Cook recommends that 

 experiments be begun by planting a 

 number of Castilla rubber trees in Porto 

 Rico and the Philippines, but he warns 

 the American public against investing 

 large sums in starting rubber planta- 

 tions until it has been proved that the 

 rubber tree will grow successfully on 

 these islands. 



The accompanying illustrations, for 

 the use of which the National Geo- 

 graphic Magazine is indebted to Mr 

 Cook, give interesting information about 

 the rubber tree and the native Mexican 

 method of tapping it for its milk.* 



It would seem to be a very simple 

 matter to improve on the rude gashes 

 made by the machete of the rubber 

 gatherer, but this has not proved to be 

 easy. The rubber milk is not the sap 

 of the tree and can not be drawn out by 

 boring holes in the trunk, as is done 

 with the sugar maple. The milk is not 

 in the tissues of the tree, but is con- 

 tained in delicate tubes running length- 

 wise in the inner layers of the bark, and 

 to secure milk in any quantity it is nec- 

 essary to open man}' of these tubes by 

 wounding the bark. The rubber is 

 formed in floating globules inside the 

 tubes and can not pass through their 

 walls, so that even a suction apparatus 

 would not bring it out unless the tubes 

 were cut. 



The method by which the natives of 

 Soconusco, Mexico, have been accus- 

 tomed to extract the milk is shown in 



* Consult ' ' The Culture of the Central Amer- 

 ican Rubber Tree." By O. F. Cook. U. S. 

 Department of Agriculture : Bureau of Plant 

 Industry — Bulletin 49. 



