mental impressions on the mother can
produce definite mental and emotional disposition in the child is
a special aspect of the question to which scarcely any inquiry
has been devoted. So distinguished a biologist as Mr. A.W.
Wallace has, however, called attention to this point, bringing
forward evidence on the question and emphasizing the need of
further investigation. "Such transmission of mental influence,"
he remarks, "will hardly be held to be impossible or even very
improbable," (A.W. Wallace, "Prenatal Influences on Character,"
_Nature_, August 24, 1893.)

It has already been pointed out that a large number of cases of foetal
deformities, supposed to be due to maternal impressions, cannot possibly
be so caused because the impression took place at a period when the
development of the foetus must already have been decided. In this
connection, however, it must be noted that Dabney has observed a
relationship between the time of supposed mental impressions and the
nature of the actual defect which is of considerable significance as an
argument in favor of the influence of mental impressions. He tabulated 90
carefully reported cases from recent medical literature, and found that 21
of them were concerned with defects of structure of the lips and palate.
In all but 2 of these 21 the defect was referred to an impression
occurring within the first three months of pregnancy. This is an important
point as showing that the assigned cause really falls within a period when
a defect of development actually could produce the observed result,
although the person reporting the cases was in many instances manifestly
ignorant of the details of embryology and teratology. There was no such
preponderance of early impressions among the defects of skin and hair
which might well, so far as development is concerned, have been caused at
a later period; here, in 7 out of 15 cases, it was distinctly stated that
the impression was made later than the fourth month.[196]

It would seem, on the whole, that while the influence of maternal
impressions in producing definite effects on the child within the womb has
by no means been positively demonstrated, we are not entitled to reject it
with any positive assurance. Even if we accept it, however, it must
remain, for the present, an inexplicable fact; the _modus operandi_ we can
scarcely even guess at. General influences from the mother on the child we
can easily