Demme selected his children of drunkards by selecting
children who came to his hospital on account of imperfect development of
speech, mental defect, imbecility or idiocy. When he found families in
which such defective children occurred, he then inquired as to their
ancestry. Many of these children, he found, were reduced to a condition
approaching epilepsy, or actually epileptic, because they themselves
were alcoholic. Obviously such material can not legitimately be used to
prove that the use of alcohol by parents injures the heredity of their
children. The figures do not at all give the proof we are seeking, that
alcohol can so affect sound germ-plasm as to lead to the production of
defective children.

Dr. Bertholet made a microscopic examination of the reproductive glands
of 75 chronic male alcoholics, and in 37 cases he found them more or
less atrophied, and devoid of spermatozoa. Observing the same glands in
non-alcoholics who had died of various chronic diseases, such as
tuberculosis, he found no such condition. His conclusion is that the
reproductive glands are more sensitive to the effects of alcohol than
any other organ. So far as is known to us, his results have never been
discredited; they have, on the contrary, been confirmed by other
investigators. They are of great significance to eugenics, in showing
how the action of natural selection to purge the race of drunkards is
sometimes facilitated in a way we had not counted, through reduced
fertility due to alcohol, as well as through death due to alcohol. But
it should not be thought that his results are typical, and that all
chronic alcoholists become sterile: every reader will know of cases in
his own experience, where drunkards have large families; and the
experimental work with smaller animals also shows that long-continued
inebriety is compatible with great fecundity. It is probable that
extreme inebriety reduces fertility, but a lesser amount increases it in
the cases of many men by reducing the prudence which leads to limited
families.

In 1910 appeared the investigation of Miss Ethel M. Elderton and Karl
Pearson on school children in Edinburgh and Manchester.[22] Their aim
was to take a population under the same environmental conditions, and
with no discoverable initial differentiation, and inquire whether the
temperate and intemperate sections had children differing widely in
physique and mentality. Handling their material with the most refined
st