F. W. Mott.Medicine and Eugenics.427
Recurrent insanity and epilepsy, with which it is closely allied, in relation
to hereditary transmission, is one of the most important problems requiring
scientific investigation by complete family histories and construction of
pedigrees, and I can conceive no more important work on the relation of
heredity to insanity than the following up, systematically, the history of
children born in the sane intervals of cases admitted to the asylum and
subsequently discharged.
From the statistics of relatives a computation has been made of the pro
portion of offspring who were born after the the first attack of insanity in
the parent; it was found that 46 offspring out of 581 were born after the
first attack of insanity in the parent, i.e., 7'9%. That is to say, in the
case of 529 insane parents, the birth of only one-twelfth of their 590 off
spring would have been prevented by sterilization or life segregation of the
parent after the first attack of insanity. These figures refer to the offspring
which become insane, but there are a large number of offspring who do not
become insane, and these would be cut off if life segregation or sterilization
were adopted.Single and Dual Neuropathic Inheritance.
Every pedigree is a study in itself and occupies a whole book if sys
tematically carried out as regards inheritance of characters, and the classi
fication of the same is a matter of considerable difficulty. We have not
enough systematic pedigrees yet to form precise data and conclusions upon,
but perhaps I may be permitted to refer to indications from the examination
of pedigrees of three generations which I have obtained myself and com
bined with those obtained by Dr. Wilson White and Dr. Daniel. I will
divide them into two groups :—•
Group 1. Those with a double pathological inheritance, that is, both
ancestral stocks show insanity, feeble-mindedness, drunkenness, epilepsy,
suicide, or nervous disease of various kinds, direct or collateral, within two
generations. In these 18 families there were 116 children born alive, and
100 reached adolescence, and among them were 39 insane, suicides, or
sufferers with nervous disease, and 61 apparently normal. Thus 39% of
the offspring reaching adult age were affected. But these are probably
selected pedigrees, and are not numerous enough to draw definite conclusions
from. Group 2, in which there was an insane inheritance on one side only.
Ninety families were examined. Of 384 children born alive 40 died in
early life; there were 33 insane, suicide, or nervous disease, and 311 normal.
Thus 9'6% of the offspring reaching adult age were affected.
The conclusion which possibly might be drawn is that a child born of a
dual neuropathic inheritance stands on an average a chance of being insane
four times as great as where only one stock is infected. This, however,
applies to the mass and not the individual.
It might be argued that there are a certain number of imbeciles who
could be allowed all social privileges excepting reproduction; this would
