84 
TRANSACTIONS OP THE TEXAS ACADEMY OP SCIENCE. 
The mode of development of a particular ovum is determined from the 
moment of its fertilization by a spermatozoon. It then receives certain 
tendencies which will affect cell segmentation up to its latest stages. 
It has qualities imparted to it which will produce certain results, even to 
the shape of the nose, color of the eyes and hair; aye, even qualities 
which become manifest in functions, such as tricks of manner, speech, 
expression, gait, and a thousand other peculiarities. 
On contemplation, it seems to me preposterous that an impression re¬ 
ceived by the mother after the ovum has received its stimulus to develop 
can in any way alter any of these tendencies, either functional or struc¬ 
tural, so as to give a distinct connection between the impression received 
by the mother and the defect resulting in the offspring. 
As, on the other hand, I would like to put before you an unbiased 
view of the subject, I will give an epitome of Dabney’s views on the 
subject. 
The cases collected seem to show that neither mental nor bodily defects 
are often caused by maternal impressions. 
That the defects may be due to errors of development, or marks, such 
as nsevi, moles, etc., which may be caused by circulatory or inflammatory 
disturbances. 
That the defects due to errors of development have been as a rule at¬ 
tributed to impressions received at a period of pregnancy when such 
errors are likely to occur. 
That other effects, such as marks, nsevi, etc., have occurred at a later 
date, when inflammatory affections are more liable to occur. 
That, in a large number of cases, there is a striking similarity between 
the impression received and the resulting foetal defect. 
That it is not necessary for a woman to be conscious of the impression 
or to expect a defect for such defect to occur, although in many cases the 
defect has been anxiously awaited. 
That the impressions are usually of an emotional character, and often 
unpleasant. 
That an impression of considerable violence may produce an effect in 
a few hours, although as a rule a much longer time is required. 
In concluding this section, I wish to say that the question is still sub- 
judice. The difficulties in coming to a definite conclusion are so great 
and so numerous that it would be rash to occupy a positive position with¬ 
out further evidence of a more definite scientific character being laid be¬ 
fore us. Unfortunately, mothers and some medical men are a little too 
credulous and too much inclined to find some cause for a result, even if 
they have to search into the depths of their own romantic minds. Until 
we can be sure that fact and not fiction is speaking, we are powerless to 
decide. 
