CHAPTER VI 
POPULATION AS AFFECTED BY VARIOUS CONDITIONS 
THE history of the very remarkable nineteenth cen- 
tury has compelled us to recognise what important 
factors scientific and technical knowledge and syste- 
matic organisation are in enlarging the world’s popu- 
lation-carrying capacity. The better correlation of all 
Man’s efforts in connection with his exploitation of 
Nature’s resources generally, and the more efficient 
use of the earth’s surface, are problems already com- 
manding attention. In this connection we may appro- 
priately refer to Man’s dependence on cereals. 
Cereals play such a rdle in the world’s life, that some 
idea of its population limits may be had by consider- 
ing what are the possibilities in respect of their pro- 
duction. To enable the relative values to be computed 
with great rigour, their food-values are of course really 
required. It happens, however, that the effect of 
this element is practically negligible, a fact that later 
will be fairly obvious. 
The latest available returns indicate that, omitting 
China, Siam, and some other countries, for which 
there are no statistics, the world-production recently 
was as follows: — 
Product. Wheat. Rye. Barley. Oats. Maize. Rice. 
a elories) 1560 1611 1525 1553 1710 1640 
Million arres cult 2387 92:8 647 1245 1683 1230 
Million tons yield . 89-20 33-15 2843 53:54 106-98 79°14 
Tons per acre . ©0374 ©0357 ©0439 0430 0637 0-643 
It may be noted that the yield of wheat and rye 
could be taken as about 0365 tons, of barley and oats as 
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