re
either intemperate or scrofulous, and that there were also other
predisposing causes.[70] Dr. Bemiss found that 7.8 per cent of his
3942 children of consanguineous marriages were idiots, while but 0.7
per cent of the children of non-consanguineous parentage were
idiotic.[71] A more detailed examination reveals the fact that in a
large number of these, one or both of the parents were mentally
defective. For example, in a marriage of double cousins the wife was
"feeble minded" and the six children were of inferior mentality. In a
case of first-cousin marriage the wife became insane and two of the
children were idiotic. In a case of the marriage of cousins,
themselves the offspring of cousins the husband was a hypochondriac,
and seven children idiotic. In another marriage of the same class both
parents were feeble-minded and the children idiotic. These are simply
taken at random, and many others might be given. When we find also
that in a majority of cases no report is given of the ancestry, it is
very obvious that consanguinity alone could not have been the cause of
any large proportion of the 308 cases of idiocy in the Bemiss report.

[Footnote 70: Barr, op. cit., p. iii.]

[Footnote 71: Bemiss, op. cit., p. 420.]

My own investigations show that out of 600 children of first cousin
marriage (from correspondence) 26 or 4.3 per cent are mentally
defective--10 are reported as "idiots," 13 as "weak-minded" and 3 as
"imbeciles." In at least five of these cases there is evidence of bad
heredity, in two others the father was intemperate and in two more
causes acting after birth are mentioned.

The statistics of the insane and idiotic in Prussia presented by Mayet
clearly indicate the large part which heredity plays in the production
of mental disorders. Tables XX and XXI set forth the most important
results of his work. Mayet considers a case hereditary if any near
relative of the subject suffered from mental or nervous disorder, or
was intemperate, suicidal, criminal or eccentric.[72]

[Footnote 72: Mayet, _Verwandtenehe and Statistik_, quoted by Feer,
_Der Einfluss der Blutsverwandschaft der Eltern auf die Kinder_, p.
13.]

TABLE XX.
--------------------------------------------------
| No. of |Percentage
| Cases. |hereditary.
--------------------------------------------------
1. Simple Insanity |102,097 | 31.7 = 100
Consanguineou