136 LUTHER BURBANK 



rubber ultimately be supplanted by the labora- 

 tory product. 



The method of gathering the so-called latex or 

 milky juice, which is virtually rubber in solution, 

 is curiously similar to the method of obtaining 

 the sap of the sugar maple. Indeed the latex 

 may be drawn in precisely the same way, by bor- 

 ing a hole in the trunk of the rubber tree and 

 inserting a grooved stick along which the juice 

 w r ill run into a receptacle. But the cultivators 

 are not usually content with so slow a method, 

 and there are various methods of tapping the 

 tree that expose a larger surface of the cambium 

 layer and thus extract the milky juices in larger 

 quantity. 



In the case of the wild trees it is not unusual 

 for the natives of Mexico, Central America, and 

 South America to make a series of V-shaped 

 incisions in the bark of the tree, placing a recep- 

 tacle at the point of each "V" and thus securing 

 a relatively enormous amount of fluid regardless 

 of the fact that they jeopardize the life of the 

 tree itself. 



Of course cultivated groves or plantations are 

 tapped in a more conservative way, but the prin- 

 ciple involved is everywhere the same. 



The latex of the rubber tree is comparable to 

 the sugary sap of the maple. It appears to be a 



