68 RUBBER AND 



The tree is about 80 feet high, and at about ten feet 

 from the ground it divides into three main branches 

 each about four feet in girth. In comparison with the 

 girth at the base of the trunk, the crown of the tree is 

 by no means extensive. In fact the volume of the 

 bark per foot of altitude probably falls off rather than 

 increases as we pass upwards, since although the total 

 circumference of the branch system increases, the thick- 

 ness of the bark rapidly diminishes. We may therefore 

 assume with some degree of confidence that the total 

 volume of the laticiferous system of the whole tree does 

 not exceed 5000 cubic inches, and is probably very 

 much less. Even if this very liberal estimate be adopted, 

 the whole system must have been emptied twice over 

 in the space of three years. At the end of this period 

 the vessels were still full of latex, and the freedom of 

 flow had increased rather than diminished. 



Origin of Latex. 



What is the source of this very large supply? It has 

 been suggested that the latex may be manufactured in 

 the leaves and pass down the tree to the wounded area. 

 Now Hevea is a deciduous tree and in Ceylon drops the 

 whole of its leaves in February or March. There may 

 be an interval of nearly a month between the loss of 

 the old leaves and the time when the young leaves 

 become fully functional. Hence, if the leaves represented 

 the chief source of the latex supply, we should expect 

 the yield of latex to be reduced almost to nothing 

 shortly after the fall of the leaves, if tapping be carried 



