454 SOME GENERAL PROBLEMS OF DEVELOPMENT 



which is a non-nervous tissue, and mysteriously affect the nervous 

 system of the foetus. 



As a matter of fact, the female does not seem to exercise a pre- 

 ponderating influence even upon the normal phases of develop- 

 ment, as might be supposed since the offspring are nourished 

 within her body. If this were the case, one would expect to find 

 children resembling their mothers to a greater degree than their 

 fathers, whereas the resemblance is about equally divided, as in 

 other forms of development. Moreover, there is no direct evidence 

 for such prenatal influences as are popularly supposed to exist. 

 Malformations are explained by causes other than the mental or 

 physical states of the parent. It is true that conditions of mal- 

 nutrition in the mother and specific poisons in her blood, such as 

 lead poison or the toxins of certain diseases, may affect the embryo 

 in the same way that a frog embryo might be affected by sub- 

 stances in the surrounding water, or a chick embryo by substances 

 introduced into the albumen of the egg and by the atmosphere of 

 an incubator. Insofar as belief in prenatal impressions leads to a 

 state of fear in pregnant women, it is a cruel superstition no better 

 than belief in witchcraft. The more pleasant belief that a mother 

 can make the eyes of her child a desired color by so wishing, or 

 create a musician by listening to music, rests upon no better foun- 

 dation. What is probably true is that the body of a nervous and 

 overwrought mother is less able to carry on the processes neces- 

 sary for the proper nutrition of her child, whether in the foetal 

 stages or during nursing; while contentment resulting from the 

 belief that something is being accomplished, even though it rests 

 upon a false foundation, makes for good digestion and hence for a 

 metabolism that results in better nutrition of the foetus. 



Telegony. — Correlated with the belief in prenatal influences 

 is that in telegony. It is widely believed among breeders that if 

 a pure-bred female is mated with an inferior male her offspring by 

 subsequent matings with pure-bred males will show the influence of 

 the previous sire. This belief rests upon many alleged examples 

 and was once supposed to possess some scientific foundation. 

 Scientific study, however, gives no indication of any such influence, 

 and on theoretical grounds there is no warrant for the belief. The 

 inheritance from the male is in some manner carried in the sper- 

 matozoa. These are introduced by sexual union and, so far as the 

 evidence goes, they do not remain alive in the female mammal for 



