go EXPLOITATION OF PLANTS 
of the plant exploited. Further, such study and ex- 
ploitation must be effected in close inter-relation with 
the consumer, if the results are to have practical 
significance. There are scientific workers in various 
countries studying the cotton plant, and the British ones 
have shown the way in more than one case to their 
American colleagues, who had a very long start, but 
from the nature of the case their nominal official work 
consists rather of Investigation as we have defined it, than 
of deep-digging Research. There could be no more 
convincing example of the vagueness of our present 
knowledge than the fact—almost incredible—that only 
during the present decade have the U.S.A. growers 
discovered how to increase their yield per acre by 30 
per cent. at no cost; the method is simply to leave 
twice to three times as many seedlings standing on the 
area as had previously been the custom. Incidentally 
it may be added that the Egyptian fellah many years ago 
discovered the equilibrium-point in this system of 
diminishing returns, on his own account, by the accumu- 
lated experimental evidence involved in growing and 
selling his crop, and he has steadily resisted the 
well-intentioned efforts of would-be reformers with 
smatterings of biology, who wished him to adopt wider 
spacings of his plants. The present writer studied 
the principles involved, and America has now copied 
the practice. 
If another example were needed, it might be found 
in Mr. Leake’s assertion that the whole of the work on 
the introduction of exotic cottons into India during more 
than a century needs to be repeated ab initio. The 
cotton flower was always assumed to be self-fertilised, 
