LUTHER BURBANK 



There are certain classes of juicy exudates, 

 however, which appear to have characteristics that 

 make them useful to plants of many types. Promi- 

 nent among these are the milky juices that when 

 dried constitute rubber, and the resinous ones that 

 constitute tars and resins and turpentine. 



Nothing could be physically much more dis- 

 similar than a piece of rubber and a teaspoonf ul of 

 oil of turpentine. 



But the chemist tells us that each of these sub- 

 stances is composed exclusively of the two ele- 

 ments carbon and hydrogen; the only difference 

 being that the turpentine molecule has 10 atoms of 

 carbon and 16 of hydrogen, whereas the molecule 

 of rubber has 8 carbon atoms and 7 atoms of 

 hydrogen. 



Just how the elements are compounded, and 

 just why they should make up substances of such 

 unique characteristics when brought together in 

 these particular proportions, even the chemist does 

 not know. Nor, until recently, was he able to dupli- 

 cate the feat of building up these complex mole- 

 cules, even though he is perfectly familiar with the 

 general properties of the atoms of both carbon 

 and hydrogen. 



In very recent years, however, chemists have 

 been at work on the problem of compounding the 

 atoms in such a way as to get them together in the 



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