We can, again, as suggested by Féré, very well believe that the maternal emotions act upon the womb and produce various kinds and degrees of pressure on the child within, so that the apparently active movements of the _fœtus_ may be really consecutive on unconscious maternal excitations. We may also believe that, as suggested by John Thomson, there are slight incoördinations _in utero_, a kind of developmental neurosis, produced by some slight lack of harmony of whatever origin and leading to the production of malformations. We know, finally, that, as Féré and others have repeatedly demonstrated during recent years by experiments on chickens, etc., very subtle agents, even odors, may profoundly affect embryonic development and produce deformity. But how the mother’s psychic disposition can, apart from heredity, affect specifically the physical conformation or even the psychic disposition of the child within her womb must remain for the present an insoluble mystery, even if we feel disposed to conclude that in some cases such action seems to be indicated. Direct evidence of the physical aspect of my thesis is found in the fact quoted by Marshall in _The Physiology of Reproduction_, 1910, p. 566:-- So also it has been found that immunity from disease may be acquired by young animals being suckled by a female which had previously become immune, the antibody to the disease being absorbed in the ingested milk. Further argument upon these lines might well be brought forward in favour of the view that the potential mother, during the months whilst she is acting as the child’s total environment in all physical ways, is also through her mental states and conditions affecting the child’s ultimate mentality and artistic and spiritual powers. This subtle control exerted over the formation of the child may be visualized as more like some effect parallel to the remote influences of the internal secretions in controlling the other organs of the body than the more mechanical picture of things visualized by the Mendelians and those who concentrate on the purely physical and material aspects of heredity as related to chromosome structure.