34 
done by planters to improve the natural production. 
The moral is obvious, and is, I think, fully realized by 
leading rubber planters. Already important improve- 
ments in production have been effected and the cost so 
considerably reduced on many estates that the com- 
mercial success of synthetic rubber seems a_ highly 
improbable contingency. 
In all industries risks have, of course, to be taken, 
and there are some against which no human foresight 
can provide. It has more than once been suggested 
that it is by no means without the range of possibility 
that tyres might be constructed on a different principle, 
involving the use of metal with little or even no rubber. 
The way to minimize this risk is to extend the industrial 
uses to which rubber is applied, and definite steps are, 
it is understood, now being taken to this end. 
I have made this brief allusion to the rubber problems 
of to-day because they point to a condition of affairs 
which, so long as it is allowed to continue, is a serious 
menace to the proper progress of tropical agriculture. 
The extraordinary development of the rubber-growing 
industry has, from the scientific standpoint, taken us 
unawares. A large and rapidly increasing industry was 
suddenly confronted with a number of questions which 
no one could properly answer, for the good reason that 
the necessary knowledge did not exist. The exact 
origin, nature, and functions in the tree of the latex 
which carries the rubber were not known, and are not 
precisely known even to-day. These problems belong 
mainly to the regions of botanical physiology and of 
chemistry, but had been little investigated. They lie 
at the root of the many practical questions which arise 
in connection with the production and flow of latex, the 
relation of latex production to the nutrition of the tree, 
and the methods of securing a steady production of 
latex without undue interference with the vitality and 
growth of the tree. Little was known as to the effect 
on the tree of the continuous removal of latex or of the 
relative effect of different methods of tapping. The 
consequence was that these investigations have had to 
be carried out while the plantations waited for the know- 
ledge, which has now been largely gained in part 
through observations and experiments made by practical 
planters. 
