RUBBER PLANTING 53 



Composition of Hevea latex. 



Fresh latex as it flows from the tree consists of a 

 fluid emulsion which closely resembles rather thin cream 

 in general appearance. The composition is also some- 

 what similar, except that the fats of the cream are 

 replaced by a different hydrocarbon. This hydrocarbon 

 has the empyrical formula C 10 H 16 , which is the same as 

 that of solid rubber. In the latex, however, the rubber 

 probably exists in a liquid form. In this case the 

 process of coagulation is either accompanied or followed 

 by solidification of the rubber globules. The liquid 

 hydrocarbon existing in the latex is believed to undergo 

 polymerisation to form true rubber by the coalescence 

 of several comparatively simple molecules into one of 

 a more complex character. In freshly drawn Hevea 

 latex the rubber globules are, on the average, approxi- 

 mately one-thousandth of a millimetre in diameter, but 

 many smaller globules also occur. In other latices the 

 globules may be somewhat larger, but their size pro- 

 bably seldom exceeds one ten-thousandth part of an 

 inch. The further study of such minute bodies is 

 naturally a difficult matter, but it is believed that the 

 rubber or simpler hydrocarbon is kept in emulsion by 

 the existence of a thin skin surrounding each globule, 

 and that this skin is either of a resinous or of a proteid 

 nature. 



According to various estimates the composition of 

 the latex of Hevea is approximately as follows: 



