VIII THE DEVELOPMENT OF HUMAN RACES 173 
Different Effects of Natural Selection on Animals and on Man 
In order to answer these questions, we must consider why 
it is that natural selection acts so powerfully upon animals, 
and we shall, I believe, find that its effect depends mainly 
upon their self-dependence and individual isolation. A slight 
injury, a temporary illness, will often end in death, because 
it leaves the individual powerless against its enemies. If an 
herbivorous animal is a little sick and has not fed well for a 
day or two, and the herd is then pursued by a beast of prey, 
our poor invalid inevitably falls a victim. So, in a carnivor- 
ous animal, the least deficiency of vigour prevents its captur- 
ing food, and it soon dies of starvation. There is, as a 
general rule, no mutual assistance between adults, which 
enables them to tide over a period of sickness. Neither is 
there any division of labour; each must fulfil all the con- 
ditions of its existence, and, therefore, natural selection 
keeps all up to a pretty uniform standard. 
But in man, as we now behold him, this is different. He 
is social and sympathetic. In the rudest tribes the sick are 
assisted, at least with food; less robust health and vigour 
than the average does not entail death. Neither does the 
want of perfect limbs or other organs produce the same effects 
as among animals. Some division of labour takes place ; the 
swiftest hunt, the less active fish, or gather fruits ; food is, to 
some extent, exchanged or divided. The action of natural 
selection is therefore checked ; the weaker, the dwarfish, those 
of less active limbs, or less piercing eyesight, do not suffer the 
extreme penalty which falls upon animals so defective. 
In proportion as these physical characteristics become of 
less importance, mental and moral qualities will have increas- 
ing influence on the well-being of the race. Capacity for 
acting in concert for protection, and for the acquisition of 
food and shelter ; sympathy, which leads all in turn to assist 
each other; the sense of right, which checks depredations 
upon our fellows ; the smaller development of the combative 
and destructive propensities ; self-restraint in present appe- 
tites, and that intelligent foresight which prepares for the 
future, are all qualities that from their earliest appearance 
must have been for the benefit of each community, and would, 
