38 THE RUBBER TREE BOOK 



organized body has first been likened to a machine. The 

 cells will be the pieces of the machine, the organism their 

 assemblage." 



If we apply this description to the Hevea tree it will at once 

 be seen to be a ludicrously inadequate conception. Even if 

 we regard the tree as a factory full of diverse machinery it gives 

 quite an insufficient idea of the facts of the case. To arrive at 

 a true understanding of the realities we must rather imagine 

 the tree as a well-equipped city, full of activity, and with a large 

 and thriving population. If we portray to our minds such a 

 picture we shall find that there are present, and in active 

 operation in the organization called a tree, what we might 

 legitimately describe as gas-works, train services with well- 

 laid-out routes and apparently many thousands of attentive 

 and intelligent porters, and pumping installations with in- 

 visible engineers to attend to them and to execute any 

 necessary alterations or repairs. There are chemical works 

 in the tree-city, where a large number of chemical pro- 

 ducts are manufactured, such as various colouring matters, 

 starches, sugars, proteins, resins, oils, and, of special interest 

 to the planter, caoutchouc. There is also a well-laid-out 

 drainage system. 



With regard to the gas-works, which we have mentioned 

 as being present in the tree-city, the leaves, during all the 

 hours of daylight, are constantly at work, taking in carbonic 

 acid gas from the atmosphere, turning out oxygen gas and 

 manufacturing carbon compounds. The gas-works of our 

 cities and towns are much more crudely conceived and less 

 efficient. 



Throughout the stem of the tree there are, as has been 

 stated, well-laid-out routes of what might be described as 

 tubular railways. There is the route via the sap-wood, where 

 the food in solution derived from the soil is sent up to the manu- 

 facturing centres situated in the leaves of the tree, and to other 

 parts. Another important route to serve this great organiza- 

 tion passes downward through the bast in the inner bark, 

 carrying the manufactured food in the form of sugar and other 

 products. The bast lies close to the wood and contains, among 

 other elements, a system of conducting tubes (sieve-tubes). 

 There are also what are known as the medullary rays, vertical 



