144 



ANALYSES OF HEVEA LATEX. 



Messrs. Clayton, Beadle and Stevens have sent an interesting 

 paper on some Analyses of Hevea latex published in " The Analyst " 

 ofJanuar\% 1911. One of the interesting points is the comparison of 

 latex from the leaf stalks of the Para rubber tree with that of the 

 trunks of trees four and ten years old. 



It is now many years since an attempt was made at the Botanic 

 Gardens, Singapore, to extract latex from the leaf stalks of the Para 

 rubber tree. M. Arnaud, the inventor of the extraction of Gutta 

 percha f-om the leaves, was trying the same process on the leaf 

 stalks and twigs of Hevea brasiliensis, and a large quantity of boughs, 

 tops, etc., of Hevea was supplied to him. His process for extracting 

 the Gutta percha from Dichopsis gutta leaves was to grind the leaves 

 and twigs to powder and immerse them in water, the refuse eventually 

 sank, and the Gutta percha floated on the water whence it was skim- 

 med off. He tried, as did I, this process on Hevea twigs and leaves 

 but the only result was a dirty looking solution in which no rubber 

 could be seen. 



M. Arnaud got some more leaves and twigs and took them oft' to 

 try again and some days later I met him, as I was driving out, waving 

 triumphantly a piece of rubber in his hand. 



After trying many methods, he had succeeded in making the 

 piece of rubber by rolling the twigs and petioles with a warmed 

 wooden roller. The rubber adhered to the roller and was then 

 peeled off. It was very tacky and soft, and owing to the abandonment 

 of topping trees, which would have suppUed material and the poor 

 quality of the rubber produced, the experiments were not carried 

 further. 



Messrs. Clayton, Beadle and Stevens have been investigating the 

 rubber from the leaf stalks of Para rubber, and say that " the dried 

 latex is at first rather tacky but on keeping a month or two and 

 passing between steel rolls it is no longer adhesive and somewhat 

 resembles a high class purified Guayule rubber. It is pale in colour, 

 but rather soft, and much weaker than rubber from the bark of 

 mature trees." 



The authors give then the analysis of this rubber compared with 

 that of four and ten years old. 



Dried latex From 10 



from leaf stalks. From 4 year old. year old. 



Acetone Extract (resin) ... 7.12 4.00 4.13 



Protein 13. 02 4.90 5.08 



Ash 1. 19 0.80 1.75 



Caoutchouc (by difterence) 78.67 00.24 89.04 



