F. W. Mott.Medicine and Eugenics.419
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Fig. 11Fig. 12Fig- 13
offspring of an insane parent occurs in four or five. The occurrence of in
sanity in all the children is probably due to the fact that there is a
double insane inheritance in all these instances, although it is only shown
in one completely, and one partially.
Fig. 14. Two total abstainers, but born of drunken parents (circles
with cross)and with direct and collaterial insanity in stocks (black figures),
give birth to eight children, the first two are healthy and grown up, the
second with numerous children; then come two children (shaded circles)
dying in early life, followed by a son and two daughters (black figures)
all suffering from dementia of adolescence, and lastly a healthy daughter
with children. What we want to know is this : have all the unsound elements
been segregated out? This can only be ascertained by following up the
children of the sound or apparently sound members.
Everybody knows the value of coming from a good stock or a bad stock,
and in judging whether an individual who is insane should marry and pro
pagate or not it is absolutely necessary as the study of a large number of
pedigrees shows that we should consider (1) the nature of the insanity, and
(2) what was the cause. Certain forms of insanity are much more likely
to be transmitted than others either in the same form or still more fre-
Fig. 14
The Importance of Ancestral Inheritance.ee 2
