less
obvious changes denoted by function, can be perpetuated and
strengthened. That the Semitic race excels in commerce is probably due
to the fact that the variation of the brain which affected favorably
the mental action conducive to this form of activity, was favorable
for the race in the hostile environment in which it was usually placed
and transmitted and strengthened by close intermarriage. It is
impossible, however, to form a conception of what may be regarded as
an ideal type of the human species. The type which might be ideal in a
certain environment might not be ideal in another, and environment is
probably of equal importance with the material. The eugenics movement
has enormously stimulated research into heredity by the methods both
of animal experimentation and observation, and study of heredity in
man. As in all of the beginning sciences there is not the close
inter-relation of observed facts and theory, but there is excess of
theory and dearth of facts. Certain considerations, however, seem to
be evident. It would seem to be evident that individuals should be
healthy and enabled to maintain themselves in the environment in which
they are placed, but the qualities which may enable an individual
successfully to adapt himself to factory life, or life in the crowds
and strong competition of the city, may not be, and probably are not,
qualities which are good for the race in general or for his immediate
descendants. At present our attempts to influence heredity should be
limited to the heredity of disease only. We can certainly say that
intermarriage between persons who have tuberculosis or in whose
families the disease has prevailed is disadvantageous for the
offspring; the same holds true for insanity and for nervous diseases
of all sorts, for forms of criminality, for alcoholism, and for those
diseases which are long enduring and transmitted by sexual contact
such as syphilis and gonorrhoea. It is of importance that the facts
bearing on the hereditary transmission of disease should become of
general knowledge, in order that the dangers may be known and
voluntarily avoided. No measures of preventive medicine are successful
which are not supported by a public educated to appreciate their
importance, and the same holds true of eugenics. How successful will
be public measures leading to the prevention of offspring in the
obviously unfit by sterilization of both males and females is
uncertain. It is doubtful w