52 EVOL.UI ION MADE PLAIN 
to environment the ancestral traits or char¬ 
acters, good and bad, of each creature. From 
these inherited traits environmental laws se¬ 
lect and nourish those best fitted to each par¬ 
ticular environment, and neglect, repress or 
destroy the less fit. At the birth of the in¬ 
dividual heredity has done its work, for good 
or ill; then environment receives the legacy 
bequeathed by its ancestry and completes the 
job—whether for the individual’s weal or woe 
depends both upon the quality of the material 
heredity handed down, and upon the character 
of the particular environment that works upon 
the material. As prior to birth heredity is the 
only factor in producing the individual, the ab¬ 
solute necessity of preventing the reproduction 
of the unfit, the inferior, becomes apparent; 
as after birth environment is the only factor, 
or sum of factors, in his production, the making 
the best possible environment for every one 
is the one absolute essential. 
The individual man, no less than other or¬ 
ganisms, is a creature of heredity and environ¬ 
ment. This is as true of his intellect and of 
his moral character as of his body. He is not 
a thing separate and apart, but a link in the 
chain of cause and effect. He is orbit-bound 
as planets are. Every thought of his brain, 
every desire of his heart, every deed of his 
hand is a natural and (circumstances consid¬ 
ered) unavoidable result of the laws of Nature 
working in and through him—as surely as 
every cause produces an effect and that every 
cause is itself an effect of a prior cause. In 
cases where opposing forces or influences tend 
