CHAPTER VI 



THE STEM 



1^ HE stem or trunk of the Hevea is the portion of the tree 

 which comes nearest to the planter, and which interests 

 him most. How very interesting the stem of the Hevea can 

 be, when rightly viewed, is a subject of which some planters 

 are very highly ignorant. To many planters the stem of the 

 Hevea is the stem of the Hevea and there is nothing more to it. 

 They recognize, of course, that the stem is composed of various 

 layers: i.e. (i) The heart-wood; (2) the sap-wood; (3) the 

 cambium; (4) the inner layer of the bark (cortex) containing 

 the laticiferous vessels; (5) the outer layer of the bark (the 

 bark proper). To them " the age of miracles is past," and 

 wonders are worked before their eyes without their being 

 aware of the fact. 



One writer says: "As the untutored savage explains the 

 movements of a watch by attributing them to a spirit which 

 has entered into it, so many writers hold that the activities of 

 living matter are due to some special and mysterious vital force. 

 They attempt to bridge the gaps in our knowledge by giving 

 them a name. This is no scientific method. Science advances 

 by explaining, that is, describing, the unknown in terms of the 

 known." 



This is most amusing. If describing a thing that is un- 

 known by giving it a title is not doing exactly what he com- 

 plains of, the English language is hard to be understood. One 

 might know the name well enough; it might be Tom, Dick 

 or Harry, but it would be no explanation of electricity, for 

 example, let alone of the mysteries of life. 



The writer goes on to say : " If vital force is merely a general 

 term for these new properties manifested in new mechanisms 

 of increasing complexity, there is no harm in it ; certainly living 

 matter must display properties not found in simpler substances, 



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