88 DOMESTICATED ANIMALS AND PLANTS 
and stops. Nature does not aim at perfection, but every species 
is just as good as competition makes it, and no better. 
Writers when discussing this topic often overstate the facts, 
They are impressed by the niceties of adjustment so frequently 
seen in nature, and rush to the assumption that everything is 
perfectly adjusted and perfectly adaptive. It is better to under- 
stand that upon the whole characters are and must be /zghly 
but not perfectly adaptive, that such adaptations are achieved 
at great distress to individuals and temporary danger to the 
_ species, and that they will never be more numerous or closer 
than circumstances compel; so that each species generally sur- 
wives with one or more handicaps, in which the fatalities are 
not sufficient to force a fit upon the one hand or bring about 
extinction upon the other. 
Looked at in this way, the animals and plants of the forest as 
we see them, even in a state of nature, represent a choice but 
not a perfect lot, born, upon the whole, as they are, from a 
highly selected though not perfect ancestry; that is, from the 
standpoint of nature these species were already highly bred 
when first domesticated by our forefathers. 
Our standards of selection differ from those of nature. In 
nature selection is based only on the struggle for existence. 
Nothing avails that does not bear upon the supreme issue of 
mere ability to live and reproduce fast enough to keep ahead of 
the death rate and thus maintain the balance of life in favor 
of the species. Natural selection is thus based on anything and 
everything that affects the mere question of life, death, and 
reproduction, and nothing else. It secures, of course, great vigor, 
comparatively long life,! and at least a reasonable degree of 
fecundity together with the extreme development of whatever 
physical part or trait of character is directly concerned with the 
preservation and sustenance of life, and there it will stop. 
1 See Fig. 12. This is the same burro shown on page 7 in his working out- 
fit, when engaged in building the Pikes Peak Railroad many years ago. His 
Jabors are done and he is now kept for photographic purposes. Ie illustrates 
the longevity of rare individuals. 
