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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 we 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, 
