130 THE RUBBER TREE BOOK 



much effort which could have been more usefully employed in 

 a less degree and at less expense. 



As a storage of water-supplies latex is again a poor contriv- 

 ance on the part of the tree, if, as said by some, that is the idea 

 it has in view. This is the weakest suggestion. The tree is a 

 habitant, not of arid sands and regions of minimum rainfalls, 

 but of moist soils and districts with abundant showers. 



There are still others who argue that latex also consists 

 of excretory matter of the tree cells which empties into the 

 channels through which pass food supplies. It is true that 

 some plants are supposed to excrete poisonous matters from 

 their systems, but one would scarcely expect an advanced tree 

 like the Hevea to deliver its excretions into its pantry. The 

 function, then, of latex considered purely from the tree's point 

 of view is somewhat obscure. No doubt many are prepared 

 to pronounce with confidence on the subject, but to such one 

 might say, as Disraeli said to an over-confident and conceited 

 junior, " My dear fellow, always remember that none of us, 

 not even the youngest, is infallible! " 



The latex of the Hevea is composed of an alkaline fluid 

 in which the minute globules of caoutchouc are held in a state 

 of suspension. In this fluid, in a state of solution, are small 

 percentages of sugars and various proteins, while starch-grains 

 and resins also are present. Latex is usually of a bluish- 

 white colour, but, on occasion, is yellow and sometimes almost 

 black. While the latex of very young trees contains a slightly 

 higher proportion of resins than that of more mature trees, 

 the rubber from young trees has practically the same composi- 

 tion as rubber from old trees when tested by chemical analysis. 

 That does not mean that the one rubber is equal in quality to 

 the other. The chemical analysis of many products is the 

 same, although the articles are very widely different. Glucose 

 and malt extract, for example, have the same chemical com- 

 position, but malt extract is a very different thing from glucose 

 and can convert starches into sugars while glucose leaves them 

 untouched. To take a case more common: the cellulose of 

 wood pulp has the same chemical composition as the cellulose 

 of cotton, but nothing like the same tensile strength. The fact 

 is that chemical analysis, while helpful, cannot be relied upon 

 as a final test. With rubber the final test is vulcanization. It 



