142 



is turned out on to the dirty floor for sampling. Now there 

 is no reason why all this should exist. It would be perfectly 

 simple to pack rubber in such a way in cloths, for instance 

 that it should arrive in a fit condition to be used straightaway. 



Now, Sir, if I might for one moment look at the question 

 of variability in its scientific aspect, I think we must all agree 

 that the differences, such as they are, can be due first of all 

 to differences in the rubber substance as such, and secondly, 

 to differences in the quantity and quality of the so-called 

 secondary products or impurities. Professor Dunstan, some 

 little time back, told us that chemical analysis was of very 

 little value for the purpose of the evaluation of plantation 

 rubber, and I think I agree with that, and he proceeded to say 

 that the reason was that we had not yet developed a system 

 of analysis which was able to differentiate between the 

 " caoutchouc " present in the various qualities of rubber. In 

 this connection some interesting work has recently been pub- 

 lished by Caspari, which revives the theory of two different 

 qualities of rubber in the crude substance, the so-called pectous 

 variety and the so-called soluble variety. This work requires 

 confirmation, but it is well worth following up. For instance, 

 if we could be certain by analysis that all rubbers did contain 

 these two main varieties, and if we could show how much there 

 is in each sample, we might then be able to get over the 

 laborious experimental work connected with vulcanization. At 

 present of course that is out of the question. Secondly, 

 there is the question of the presence of the so-called impurities, 

 of the influence of the resin, of the insoluble matter, of the 

 protein, and so on. In recent years important work has been 

 done on this subject by, among others, Simon, Spence, Weber, 

 and by Dr. Stevens, and it certainly appears that there is some 

 connection between the quantity and the nature of these 

 secondary impurities and the curing properties of the rubber. 

 There is, however, no evidence yet to show that there is a 

 direct connection. 



There is one other point on which I should like to make a 

 remark, and it is this : We hear all sorts of opinions expressed 

 regarding the causes of the variations age of trees, locality, 

 time of collecting the latex, the various operations of the 

 factory, and so on and so forth. Might I say that we should 

 abandon the system of giving opinions on these points, or 

 asking for opinions that what w r e want are facts. A number 

 of these points have been worked on by the chemists of the 

 Rubber Growers' Association and other bodies in the East, 

 and they are gradually being elucidated, but it would require 

 very much time to investigate thoroughly all these problems. 

 Meanwhile, might I ask planters, manufacturers and others, 



