iv Proceedings. {October 2nd, 1906. 



examination of the cells containing these glistening threads ('92), 

 and found them to be long unbranching cells, originating in 

 pairs in the cortical tissues, and penetrating thence into the 

 neighbouring parts, in the case of the stem, largely into the 

 secondary bast. The fact that the threads are insoluble in 

 alcohol, in acids, and in alkalies, while swelling up in ether and 

 dissolving in chloroform, together with other reactions, led me 

 to the conclusion that they were not of the nature of gum, but 

 probably some form of caoutchouc or rubber such as is found 

 in the milk-containing cells (latex cells; so characteristic of the 

 family of Euphorbiaceae in which the plant had been placed by 

 Prof. Oliver. 



When some years later Messrs. Vilmorin, Andrieux & Co., 

 of Paris, had imported some living plants of Eucommia, a re-in- 

 vestigation by Messrs. Dybowski and Fron ('99) resulted in 

 establishing the fact that the elastic threads did not consist of 

 caoutchouc, but of the allied substance gutta percha, which 

 agrees with rubber in many of its chemical and physical proper- 

 ties. A striking difference, however, is the fact that when gutta 

 percha is placed in hot water it can be moulded, and whatever 

 shape is given to it is retained when it becomes cold. 



Gutta percha is derived mainly from a tree known as 

 Dichopsis gutta (Benth. and Hooker), formerly placed in the 

 genus Isonandra. This tree, known to the Malays as "Taban 

 Merah," is a native of the East Indies, and possesses a milky juice 

 or latex containing the gutta. To obtain it the tree is generally 

 felled and stripped of its bark from which the latex flows out 

 with some difficulty, often accelerated by beating. From the 

 coagulated latex the gutta percha is obtained by a process of 

 purification, consisting largely of boiling it in water. 



Of course the felling of trees for this purpose is a very 

 destructive method, and seriously endangers the sources of 

 supply. Besides this, only a portion of the gutta is obtained, 

 and that contained in the leaves more particularly is lost. If 

 the leaves of the gutta-percha tree are broken asunder, elastic 



