It is not only a powerful force among the normal, but with us to-day it
is powerfully operative. Amongst the defectives it does not and cannot
exist.

Apart from observation and statistics, therefore, it can be shown that
the birth-rate amongst the unfit is undisturbed. They marry and are
given in marriage, free from all restraint save that of environment, and
worst of all they propagate their kind.

Dr. Clouston says (Clinical Lectures on Mental Diseases, 4th Ed., p.
330) "As we watch children grow up we see that some have the sense of
right and wrong, the conscience, developed much sooner and much stronger
than others; just as some have their eye teeth much sooner than others;
and looking at adults, we see that some never have much of this sense
developed at all. This is notoriously the case in some of those whose
ancestors for several generations have been criminals, insane or
drunkards." Again (p. 331) "We know that some of the children of many
generations of thieves take to stealing, as a young wild duck among tame
ones takes to hiding in holes, and that the children of savage races
cannot copy at once our ethics nor our power of controlling our actions.
It seems to take many generations to redevelop an atrophied conscience.
There is no doubt that an organic lawlessness is transmitted
hereditarily."

Mr. W. Bevan Lewis says (A text-book of Mental Disease, p. 203) "It is
also notable, that in a large proportion of cases, we find the history
of ancestral insanity attached to the grand-parents, or the collateral
line of uncles and aunts, significant of a more remote origin for the
neurosis. The actual proportion of cases revealing strongly-marked
hereditary features (often involving several members of the subject's