development of a function in offspring
begins at the point where it _began_ in his parents, not at the point
where it _ended_ in them. Biological improvement of the race (and such
improvement greatly fosters all other kinds) must be made through a
selective birth-rate. There is no short-cut by way of euthenics, merely.
We must now consider whether there is any direct way of impairing good
heredity. It is currently believed that there are certain substances,
popularly known as "racial-poisons," which are capable of affecting the
germ-plasm adversely and permanently in spite of its isolation and
protection. For example, the literature of alcoholism, and much of the
literature of eugenics, abounds with statements to the effect that
alcohol _originates_ degeneracy in the human race.
The proof or disproof of this proposition must depend in the last
analysis on direct observation and carefully controlled experiments. As
the latter cannot be made feasibly on man, a number of students have
taken up the problem by using small animals which are easily handled in
laboratories. Many of these experiments are so imperfect in method that,
when carefully examined, they are found to possess little or no value as
evidence on the point here discussed.
Hodge, Mairet and Combemale, for example, have published data which
convinced them that the germ-plasm of dogs was injured by the
administration of alcohol. The test was the quality of offspring
directly produced by the intoxicated animals under experiment. But the
number of dogs used was too small to be conclusive, and there was no
"control": hence these experiments carry little weight.
Ovize, Fere and Stockard have shown that the effect of alcohol on hen's
eggs is to produce malformed embryos. This, however, is a case of
influencing the development of the individual, rather than the
germ-plasm. Evidence is abundant that individual development can be
harmed by alcohol, but the experiments with eggs are not to the point
of our present purpose.
Carlo Todde and others have carried out similar experiments on cocks.
The conclusions have in general been in favor of injury to the
germ-plasm, but the experiments were inadequate in extent.
Laitinen experimented on rabbits and guinea pigs, but he used small
doses and secured only negative results.
Several series of experiments with rats indicate that if the dosage is
large enough, the offspring can be affected.
Nice, using very small
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