JAMES E. THOMPSON—-MATERNAL IMPRESSIONS, ETC. 
83 
The age of the pregnancy should be carefully noted, as by this means 
some developmental peculiarities, which can only occur in the early 
months, will not then be ascribed to impressions received by the mother 
at a later date. Thus it would be manifestly absurd to ascribe a case of 
hypospadias to a maternal impression received in the eighth or ninth 
month of pregnancy. 
Allowing for a moment that there exists a distinct connection between 
the impression and the foetal deformity, how does it work ? 
It is excessively difficult to understand how a maternal nervous dis¬ 
turbance can affect the growth of a child in any particular direction. 
No nervous connection has been demonstrated between the foetus and the 
mother; therefore the modus operandi must be searched for in an entirely 
different channel. It is well known that certain emotions and thoughts 
on the mother’s part can so alter the uterine circulation that the foetus is 
deprived of its necessary blood supply, with the result that abortion or 
premature labor may occur. But this deficiency affects the foetal circu¬ 
lation in its entirety, and not in a partial manner. 
How the blood supply to any particular foetal organ, such as the head, 
arm, genital organs, can be so altered by certain maternal vaso-motor 
changes, is what at present baffles all our research and ingenuity. It 
seems to us that the foetus must suffer in toto or not at all. Dareste’s 
well known experiments on the artificial production of monsters throws 
some light on this subject. He found that conditions affecting the blood 
supply of the embryo are inevitably followed by developmental peculiari¬ 
ties. These conditions are: the application of heat in the neighborhood 
of the cicatricula, or the production of a temperature slightly above that 
of normal incubation. The errors of development varied of course in 
each individual experiment. These researches are exceedingly interest¬ 
ing, and point to a possible explanation in the circulatory apparatus; but 
we are confronted with the same difficulty, viz., to account for the simi¬ 
larity between the foetal deformity and the maternal impression. 
Hoist, in Keating’s Encyclopaedia of Diseases of Children, throws out 
the hint that the results may be due to the action of ptomaines and leu- 
comaines on the foetal organs, these products resulting from deficient 
oxygenation of maternal blood supplying the placenta. This theory has, 
however, very little to recommend it. How is it possible for a vaso¬ 
motor disturbance in the mother to establish a vaso-motor change in an 
exactly analagous region of the foetus without the existence of some com¬ 
plex nervous apparatus ? If this apparatus exist, it has certainly escaped 
the observation of all workers in this line. 
I here repeat what I have before insisted upon, that a vaso-motor dis¬ 
turbance must affect the placental circulation in toto or not at all. 
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