October 2nd, ipo6.] PROCEEDINGS. v 



filaments are seen . of the same kind as those shown in 

 Eucommia, the gutta percha having become solidified. (See 

 Jf'igs. I and 2.) 



Many attempts have been made to extract this solid gutta 

 from the leaves, as they contain about 9 or 10% (Obach, '99) of 

 this useful substance, and if the whole of it could be extracted the 

 yield would be about 20 times as great as that of the tree trunk, 

 which is sacrificed in the native process. For plantations of 

 gutta-percha trees this would, of course, be of the greatest 

 importance. 



But the various methods suggested and patented for extract- 

 ing gutta percha from leaves* unfortunately produce a substance 

 which is of less value than the natural product. The chemical 

 processes seem in some way to alter some of its properties, and 

 the gutta percha obtained by chemical means is less lasting, 

 especially when exposed to air and light. This is possibly due 

 to the fact that the gutta is deprived of some of the resinous 

 substances with which it is mixed in nature. 



Any process which proves successful with the leaves of the 

 gutta percha tree proper should be equally applicable to 

 Eucommia. Indeed, Messrs. Dybowski and Fron have applied 

 the procedure recommended by Jungfleish, which consists in 

 extracting the gutta with toluene, but the yield seems to have 

 been much smaller than in the case of the Dichopsis, only 2 "25 %. 

 The bark, however, is richer than the leaves, and when I 

 experimented with some dried bark in 1892 I obtained a yield of 

 about 3 per cent. 



Gutta percha has been obtained from a few other trees, 

 notably from the Balata tree (Mimusops ballata), another 

 member of the Sapotaceae, but though more readily obtained, 

 because the latex is more liquid and can be easily obtained by 



* Eng. Pat. Spec. 4252, March 1892, Dieudonne Rigole. 



,, ,, ,, 11166, June 1892, Serullas. 

 ,, ,, ,, 654, Jan. 1896, ,, 



,, ,, ,, 17936, July 1897, W. Ramsay. 



,, ,, ,, 19406, Aug. 1896, Obach. 



