132 
THE DESCENT OF MAN. 
Part L 
above primary clieek acts chiefly by restraining mar- 
riages. The greater death-rate of infants in the poorest 
classes is also very important ; as well as the greater 
mortality at all ages, and from various diseases, of the 
inhabitants of crowded and miserable houses. The 
effects of severe epidemics and wars are soon counter- 
balanced, and more than counterbalanced, in nations 
placed under favourable conditions. Emigration also 
comes in aid as a temporary check, but not to any 
great extent with the extremely poor classes. 
There is reason to suspect, as Malthus has remarked, 
that the reproductive power is actually less in barbarous 
than in civilised races. We know nothing positively on 
this head, for with savages no census has been taken ; 
but from the concurrent testimony of missionaries, and 
of others who have long resided with such people, it 
appears that their families are usually small, and large 
ones rare. This may be partly accounted for, as it is 
believed, by the women suckling their infants for a pro- 
longed period ; but it is highly probable that savages, 
who often suffer much hardship, and who do not obtain so 
much nutritious food as civilised men, would be actually 
less prolific. I have shewn in a former work , 52 that 
all our domesticated quadrupeds and birds, and all 
our cultivated plants, are more fertile than the corre- 
sponding species in a state of nature. It is no valid 
objection to this conclusion that animals suddenly 
supplied with an excess of food, or when rendered very 
fat, and that most plants when suddenly removed from 
very poor to very rich soil, are rendered more or less 
sterile. We might, therefore, expect that civilised 
men, who in one sense are highly domesticated, would 
52 1 Variation of Animals and Plants under Domestication/ vol. ii. 
p. 111-113, 163. 
