THE PRESIDENTIAL ADDRESS 19 
to-day whether the imposing achievements of physical science 
have not already, in the thought and interests of men at large, 
as well as in technical and industrial development, overshadowed 
in our educational and public policy those of biology to an ex- 
tent which threatens a one-sided development of science itself 
and of the civilisation which we hope to see based on science.’ 
Sir Walter Fletcher, whose death during the past year has deprived 
the nation of an enlightened adviser, almost startled the public, 
I think, when he said in a national broadcast that ‘ we can find safety 
and progress only in proportion as we bring into our methods of 
statecraft the guidance of biological truth.’ That statecraft, in its 
dignity, should be concerned with biological teaching, was a new 
idea to many listeners. A few years ago the Cambridge philosopher, 
Dr. C. D. Broad, who is much better acquainted with scientific 
data than are many philosophers, remarked upon the misfortune 
involved in the unequal development of science ; the high degree 
of our control over inorganic nature combined with relative ignorance 
of biology and psychology. At the close of a discussion as to the 
possibility of continued mental progress in the world, he summed up 
by saying that the possibility depends on our getting an adequate 
knowledge and control of life and mind before the combination of 
ignorance on these subjects with knowledge of physics and cherhistry 
wrecks the whole social system. He closed with the somewhat 
startling words : ‘ Which of the runners in this very interesting race 
will win it is impossible to foretell. But physics and death have a 
long start over psychology and life!’ No one surely will wish for, 
or expect, a slowing in the pace of the first, but the quickening up 
in the latter which the last few decades have seen is a matter for high 
satisfaction. But, to repeat, the need for recognising biological 
truth as a necessary guide to individual conduct and no less to state- 
craft and social policy still needs emphasis to-day. With frank 
acceptance of the truth that his own nature is congruent with all 
those aspects of nature at large which biology studies, combined with 
intelligent understanding of its teaching, man would escape from 
innumerable inhibitions due to past history and present ignorance, 
and equip himself for higher levels of endeavour and success. 
- Inadequate as at first sight it may seem when standing alone in 
support of so large a thesis, I must here be content to refer briefly 
to a single example of biological studies bearing upon human 
welfare. I will choose one which stands near to the general theme 
of my address. I mean the current studies of human and animal 
nutrition. You are well aware that during the last twenty years— 
that is, since it adopted the method of controlled experiment—the 
study of nutrition has shown that the needs of the body are much 
more complex than was earlier thought, and in particular that 
