74 EXPLOITATION OF PLANTS 
method might have had. And this difference is not the 
only one, there are others. For certain fine qualities 
of goods the fine Brazilian rubber must continue to be 
used, if the best results are to be obtained, for example 
for inner tubes, for surgical instruments, and the like ; 
but, as the plantation rubber now controls the market 
by being present in much greater quantity, it forms an 
industry per se. 
But to complete our study of tropical exploitation, 
it may be of interest to deal briefly with the steps which 
-are being taken in Brazil to meet the competition of 
the plantation rubber, which is admittedly very formid- 
able. The cost of placing the Brazilian rubber on the 
market is ahead of that of placing plantation there, 
though the increased price almost equalises it, and the 
problem is how to reduce it. Export duties, at present 
almost 20 per cent. ad valorem, are being reduced, and 
would be more rapidly reduced were it easy to get the 
enormous cultivable areas of the Amazon valley, the 
richest tropical land on earth, taken up for other kinds 
of agriculture. Rubber is the only taxable value in 
the Amazon states, and therefore provides their revenue. 
Here, one may perceive, is one of the problems of the 
kind that confront the man who is occupied with tropical 
exploitation, and which one is-apt to think, when one 
is young, and fresh from the study of science at school 
and university, are purely scientific problems, whereas 
in reality they are much more complex, and are rather 
problems of finance and political economy. Given 
the Amazon valley, one knows that land is available ; 
one knows that cacao, rice, rubber, and almost innumer- 
able crops will grow well there. Why, then, cannot 
