ld's conception, have
been under the influence of environmental conditions which assist the
germ cells in developing into vigorous babies. Many studies of eminent
people show that they are uncommonly long-lived. When deaths in war and
by accident are omitted, the average length of life of 11,000 people in
the British _Dictionary of National Biography_ was 71 years. Eminence
and the kind of constitutional vigor that leads to long life go
together.

This brings us back to the problem of fitness for marriage. If the
effect of the weather on the vigor of parents can have such an influence
on health, longevity and achievement, such conditions as diet and mode
of life may produce similar effects. This possibility adds still greater
interest to the two-edged bearing of what we have just been saying upon
the problem of fitness for marriage. In the first place it appears that
an unexpected number of weaknesses which are sometimes considered
hereditary are environmental. Nevertheless, they are also inborn and
cannot easily be eradicated by education. Therefore the chance that
ordinary normal people carry a dangerous heredity is reduced, but the
responsibility of parents to see that their children are properly born
is increased. In the second place, it becomes more evident than ever
that fitness for marriage implies intelligent willingness and
persistence in acting upon the discoveries of science in whatever way
may be best for the unborn child. We have long insisted upon the right
environment for the expectant mother during pregnancy. The new
discoveries suggest that we must insist equally upon the right
environment and manner of life before pregnancy begins.

This brings up a very interesting question upon which biologists are not
agreed. Does what has just been said about the period before pregnancy
apply to the father as well as the mother? Many biologists doubt whether
we have any proof that environmental influence can weaken the sperm
cells of the male in such a way that the offspring are thereby weakened.
Other biologists, such as Professor Pearl, of Johns Hopkins University,
and Professor C. A. Mills, of Cincinnati, have made some interesting
experiments which lead them to believe that sperm cells weakened by
environmental conditions may affect the vitality of the developing
offspring. In short, at the present time there is no agreement among
competent scientific men that the health and mode of life of the father,
as wel