LUTHER BURBANK 
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 in- 
cisions in the bark of the tree, placing a receptacle 
at the point of each “V” and thus securing a rela- 
- tively 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 
mere accident that this juice has the property of 
coagulating to form the substance called rubber 
which we now find so important. But this sub- 
stance, obviously, as man uses it, has small place 
in the economy of the plant. Coagulated latex 
would serve no better purpase in the tissues of the 
rubber tree than would coagulated blood in the 
veins of a human being. 
OILs AND RESINS 
Of course the latex of the rubber tree might 
exude when the tree received an accidental 
injury, as from a falling limb, and in such case it 
would be advantageous to the tree to have the 
juice coagulate, just as coagulated blood is useful 
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