51 S 'TRANSACTIONS OF SECTION B. 



caoutchouc for technical purposes is only yielded by some half-dozen plants, Under 

 whose names these varieties of caoutchouc pass, there can scarcely be a doubt 

 that the elastic substance in each case possesses a Aery similar, if not identical, 

 chemical structure. Nearly all the latices and similar lluids furnished by plants 

 contain more or less caoutchouc. Even opium, which is the dried juice of the 

 capsule of the poppy, contains caoutchouc, whilst the opium yielded by certain 

 Indian species contains a notable proportion. Chemistry must determine the 

 means by which caoutchouc can best be separated from these relatively poor 

 latices. In view of the increasing production of the nearly pure caoutchouc 

 which is furnished by Hevea brasilie?isis, Funtumia elastica, Castilloa elastica, 

 Ficus elastica, and a few other plants which occur or can be cultivated in several 

 of our tropical Possessions, the question is not a pressing one at the moment. 



Moreover, it cannot be doubted that chemical science will sooner or later be 

 able to take a definite step towards the production of rubber by artificial means. 



The production of caoutchouc by chemical means has, indeed, virtually been 

 accomplished in its formation from isoprene. The exact nature of this change has 

 still to be determined. When this has been done it will only remain to cheapen 

 the cost of production to make the manufacture of synthetic rubber a purely 

 practical problem. I should be the last to discourage the great extension of 

 rubber planting which is now taking place. It is warranted by the present 

 demand for the material. It has also to be remembered that the actual cost of 

 producing cultivated raw rubber, which is at present about one shilling per pound, 

 will probably be reduced, and the market price of rubber may eventually be so 

 considerably lowered that, as with quinine, the synthetic production could not be 

 profitably carried on. That is a question which involves many factors at present 

 unknown,'and only time can decide. Chemists may, however, confidently predict 

 that before the British Association again meets at York the synthetic production 

 of rubber will be a fully accomplished fact. 



As I have said, our science is concerned with nearly every problem connected 

 with the great rubber industry, and in concluding these few remarks I may allude 

 to the production of vulcanised rubber depending on the formation of additive 

 compounds of the hydrocarbon with sulphur. In this connection I should mention 

 the recent experiments of Mr. Bamber in Ceylon, which appear to show that 

 vulcanisation may be accomplished by acting on the uncoagulated latex with 

 chloride of sulphur. If this proves to be practicable, it may mean the transference 

 to the tropics of the subsidiary industry of vulcanisation, which is at present carried 

 on in Europe. 



Owing to the importance and interest which attach to the chemistry of 

 rubber, it is to form an important feature in the work of this Section at the York 

 Meeting, Papers will be contributed by some of the best known workers in this 

 field, by Profes.sor Tilden, and by Professor Harries, of Kiel, who will give an 

 account of his recent work ; whilst Mr. Pickles, of the Imperial Institute, will 

 present a report summarising the whole of our chemical knowledge of the 

 subject. 



The chemical investigation of raw materials often raises, unexpectedly, problems 

 of great scientific interest. The examination at the Imperial Institute of the 

 seeds of the Para rubber tree {Hevea brasih'ensis) has shown that they contain 

 what proves to be a valuable drying oil, and in the course of the investigation 

 it was ascertained that there is also present in the seeds an enzyme closely allied 

 to, if not identical with, lipase, which is capable of splitting the oil by hydrolysis 

 into glycerin and the free fatty acid. Subsequently, during the examination of 

 other oil seeds similar enzymes have been detected, and it would appear probable 

 that most oil seeds may prove to contain an enzyme capable of decomposing the 

 fatty constituent. 



Another subject of great chemical interest and botanical importance which has 

 come into prominence in connection with the Indian and Colonial work of the 

 Imperial Institute is to be included in a joint discussion which has been arranged 

 with the Section of Botany. I refer to the production of prussic acid by plants 

 which, as I have elsewhere suggested, it is convenient to refer to as * cyanogeneais.' 



