Now a famine may occur from several different causes, some within and
others beyond the control of man, but a failure of crops has never yet been
caused by pressure on the soil. On the contrary, famine is less likely to
arise in a country whose soil is intensively cultivated, because intensive
cultivation means a variety of crops, and therefore less risk of all the
crops failing. Moreover, during the past century famine has occurred
in Bengal, where population is dense; in Ireland, where population is
moderate, and in Eastern Russia, where population is scanty. The existence
of famine is therefore no proof that a country is overpopulated, although
it may indicate that a country is badly governed or under-developed.


(b) _Abundance_

Malthusians also claim that by means of artificial birth control we could
live in a land of abundance. They point out that, as the population of
a new colony increases, the colonists, by applying the methods of
civilisation to the rich soil, become more and more prosperous. Eventually
there comes a time when capital or labour applied to the soil gives a
_maximum_ return _per head_ of population. Once that point has been reached
any further capital or labour applied to the soil will produce a smaller
return per head of population. This "law of diminishing returns" may be
illustrated by a simpler example. Let us suppose that during one year a
market garden worked by one man has produced vegetables to the value of
L10. During the second year the garden is worked by ten men and produces
vegetables to the value of L200. It is obvious that the work of ten men has
produced twice as much per head as the work of one man, because each man
has produced not L10 but L20. During the third year the garden is worked by
twenty men and yields vegetables to the value of L300. The total yield is
greater, but the yield per head is less, because each man has produced not