440 
EFFECT OF POISONING THE FCETUS. 
child by various morbid and other peculiar conditions of the 
maternal system occurring during pregnancy. This intimate 
relation between the two circulations at the placenta is 
looked to for an explanation, not only of the transmission of 
obvious and fully-developed disease from the mother to the 
foetus, as variola and syphilis, but also of those more subtle 
and obscure changes which are likewise understood to be 
capable of affecting the child. 
Although the influence thus exercised by the mother upon 
the foetus has been known to every one for ages past, and is 
continually illustrated by striking examples, it is only com- 
paratively recently that the converse relation — the influence 
of the foetus upon the mother — has received any attention. 
The subject has been most ably brought before the pro- 
fession by Dr. Alexander Harvey, in a very interesting 
series of philosophical papers “ On the Foetus in Utero, as 
inoculating the Maternal with the peculiarities of the Pater- 
nal Organism.”* In these well-known essays, he advances 
some excellent observations, and cites many cases to show 
“ that an explanation offered by Mr. M‘Gillivray, of Huntly, 
is the true one — viz., that while, as all allow, a portion of the 
mother’s blood is continually passing by absorption (and assi- 
milation) into the body of the foetus, in order to its nutrition 
and development, a portion of the blood of the foetus is as 
constantly passing, in like manner, into the body of the 
mother; that as this commingles there with the general 
mass of the mother’s own blood, it inoculates her system 
with the constitutional qualities of the foetus ; and that, as 
these qualities are in part derived to the foetus from its male 
progenitor, the peculiarities of the latter are thereby so 
engrafted on the system of the female as to be communicable 
by her to any offspring she may subsequently have by other 
males.” 
Now, although we are in possession of absolute facts, 
which furnish clear and convincing evidence of the direct 
transmission of what may be termed accidental matter from 
the mother to the foetus, not only of certain diseases, but 
also of foreign substances — as camphor and oil in the expe- 
riments of Magendie and Dr. Williams — yet we have no such 
conclusive facts in support of the converse proposition. 
However strong the argument from analogy may be, sup- 
ported as it is by the record of cases of extreme interest, yet 
demonstrative evidence is wanting of the direct absorption of 
foreign matter from the foetus by the mother. Indeed, the 
* ‘Monthly Journal of Medical Science,’ for Oct., 1849, and Sept., 
1850. 
