AS TO THE HEREDITY OF ACQUIUED CONDITIONS. 483 



Section III. — Consideration of certain possible causes 

 OP Malformations. 



Part 1. — Mental Impressions. 



Mental impressions of the pregnant woman reacting upon the 

 developing foetus were for years supposed to be a potent factor 

 in the production of abnormalities. This question is an import- 

 ant one, since abnormalities so produced would be undoubtedly 

 somatogenic. The theory has, however, been long abandoned by, 

 I believe, all biologists. Yrolik * years ago formulated his 

 reasons for denying its action. These reasons are to ray mind 

 unanswerable, and, in order that this paper may be as complete 

 as possible, I shall reproduce them here with some additional 

 comments. 



(1) As Allen Thomson points outf, "It may be remarked that 

 tbe stage of tlie period of pregnancy at which the injury of the 

 child may take place is by no means defined, and that there is 

 no correspondence between the time or advancement of the 

 foetus and the nature of the injury. Some injuries are said to 

 have occurred or to have had their foundation laid at the very 

 moment of conception, and even occasionally before that time, 

 while others are inflicted only a few weeks before birth." Where 

 by chance the time of the supposed " impression" does coincide 

 with the malformation, and this is the case in a very small 

 minority of instances, there is no reason to suppose that the occur- 

 rence is other than a coincidence, for the reasons which follow. 



(2) " That malformations seldom, or perhaps never, agree with 

 apprehensions or fears « j)'^iori of pregnant women (Gr. Vrolik, 

 T. Zimmer, J, J. Plenck, and Burdach). On the contrary, it often 

 happens that a woman who has once procreated a malformation, 

 and is continually troubled by the fear of another similar sad 

 occurrence, may become the happ}^ mother of a second well- 

 formed child." {Vrolik.) 



(3) There is no nervous connection between mother and child 

 through which such an impression could act. There is abundant 

 evidence to show that a violent mental shock to the mother may 

 cause the death of the foetus and its subsequent expulsion. Thus 

 Priestley % says : — " There is no doubt greatly increased nervous 



* Todd's Cyclop, of Auat. & Phys., Art. " Teratology." 

 t lb. Art. '• Greneratiou." J Pathology of Intra- Uterine Death, p. 68. 



34* 



