HOW POPULATION INCREASES 63 
applied in estimating the possible population of the 
whole world?» This is a question which we must 
examine. 
In the World Population Conference of August and 
September 1927, we note that H. Brenier takes strong 
exception to Prof. East’s estimate of 2-5 acres being 
applied to the whole world. It may be, he says, 
merely the figure for the United States, and he 
declares that the half (?) of humanity does not eat beef, 
but eats fish, mentioning the great quantities of fresh- 
water fish in China. Moreover, the soya bean, con- 
taining far more proteid than beef, 33 per cent. as 
against about 21, gives quicker returns on a far smaller 
area, and a more nourishing element. Also in Java, 
people are living per capita on about one-fifth of an 
acre, eating rice. We see at once not only how the 
standard-of-living comes into the question, but also 
that advances in practical dietetics come into it also. 
Dietaries differ at least according to climates. Maurel 
(teste HL. Brenier) estimates that a male weighing 
55 kilograms, and performing light work, needs, say, 
1650 calories in a hot climate, but as much as 2750 
calories in a cold one. 
If East’s estimate, however, could properly be 
applied to the entire area of land-surface, 52-5 million 
square miles, it would indicate that no less than 
13,440 millions of inhabitants was the possible limit. 
But if, on the other hand, it ought to be restricted to 
the probable total of * productive land,” viz., 31-2 per 
cent. of the above, the possible population would be 
only about 4200 millions. One sees from this that we 
must have regard to the possibilities of a better scheme 
of culture for the world as a whole in order to estimate 
its possible population. 
If the United States proportion of 503 millions of 
acres of highly improved land, out of a total of 1903 
millions, could rightly be taken as representing the