Chap. VII. 
THE RACES OF MAN. 
247 
about the hot forests of the interior and live chiefly on 
vegetable productions ; yet these tribes resemble each 
other so closely that the Fuegians on board the “ Beagle” 
were mistaken by some Brazilians for Botocudos. The 
Botocudos again, as well as the other inhabitants of 
tropical America, are wholly different from the Negroes 
who inhabit the opposite shores of the Atlantic, are 
exposed to a nearly similar climate, and follow nearly 
the same habits of life. 
Nor can the differences between the races of man be 
Recounted for, except to a quite insignificant degree, by 
the inherited effects of the increased or decreased use of 
parts. Men who habitually live in canoes, may have 
their legs somewhat stunted ; those who inhabit lofty 
regions have their chests enlarged ; and those who con- 
stantly use certain sense-organs have the cavities in 
which they are lodged somewhat increased in size, and 
their features consequently a little modified. With 
civilised nations, the reduced size of the jaws from 
lessened use, the habitual play of different muscles 
serving to express different emotions, and the increased 
size of the brain from greater intellectual activity, have 
together produced a considerable effect on their general 
appearance in comparison with savages . 52 It is also 
possible that increased bodily stature, with no corre- 
sponding increase in the size of the brain, may have 
given to some races (judging from the previously ad- 
duced cases of the rabbits) an elongated skull of the 
dolichocephalic type. 
Lastly, the little-understood principle of correlation 
will almost certainly have come into action, as in the 
case of great muscular development and strongly pro- 
52 See Prof. Schaaff hausen, translat. in ‘ Anthropological Review, 
■Oct. 1868, p. 429. 
