obability that the offspring will exhibit morbid endowments. There
are marriages which we expect to result in the birth of congenitally
defective children, and in spite of this the offspring are healthy; and
conversely, we sometimes meet with affections which we are in the habit
of regarding as dependent upon hereditary transmission, and yet we fail,
in these cases, to find any evidence of such affections in the
progenitors. And, apart from these theoretical considerations, the
physician's advice is not of much importance, for experience teaches us
that in questions of marriage his advice is very rarely followed.

The less power we have to operate by control of the congenital factors,
the more necessary shall we feel it to be to minimise the dangers
threatening the child by influencing its environment. It is true that in
this department, as in others, there is much diversity of opinion
regarding the limits of educability. Some contend that we can mould the
child like wax, a view which prevailed especially during the "period of
enlightenment" in the eighteenth century; others maintain that organic
development is predetermined at the time of procreation, and that
subsequent influences can have no effect. Although we must be careful
not to overestimate the power of education, it would be no less
erroneous to assume that development is inalterably predetermined at the
time of procreation. This applies to the efficacy of educational
influences in general, and to educational influences affecting the
sexual life in particular. The following consideration must be given due
weight. The power of the educator is limited, not merely by the child's
hereditary dispositions, but also by the nature of its environment.
Rudolf Lehmann, in his work on Education and the Educator (_Erziehung
und Erzieher_), rightly points out that Rousseau, in his _Emile_, when
discussing the problems of education, neglects too much the influences
of environment. If we wish our reasoning to furnish us with results of
practical value, and not to remain confined to the purely theoretical
plane, we must give due weight to this consideration. This applies with
equal force to the matter of sexual education. We know that the sexual
impulse may be excited by innumerable external stimuli. Such stimuli are
continuously in operation, and the best educator has no power to exclude
their influence. The mere association of the child with persons of the
opposite sex provid