SEGMENTATION OF THE OVUM 



797 



many observations are recorded in gynecological works, showing the 

 incorrectness of this view. 



It has long been a question whether strong impressions made on 

 the nervous system of the mother can exert an influence on the foetus 

 in utero. While many authors admit that violent emotions experienced 

 by the mother may affect the nutrition and the general development of 

 the foetus, some writers of authority deny that the imagination can have 

 any influence in producing deformities. The remarkable cases recorded 

 as instances of deformity due to the influence of the maternal mind are 



Fig. 220. Four stages in segmentation of the ovum of a mouse (Sobotta) ; X, polar globule. 



not entirely reliable ; and it often happens that when a child is born 

 with a deformity, the mother imagines she can explain it by some 

 impression received during pregnancy, which she recalls only after she 

 knows that the child is deformed. There is, indeed, no satisfactory 

 evidence that the maternal mind has anything to do with the produc- 

 tion of deformities in utero. 



Segmentation of the Ovum. Soon after fertilization and the forma- 

 tion of the cleavage-nucleus, a furrow appears at the point of extrusion 

 of the polar globules. This is met by a furrow upon the opposite side, 

 and the ovum is divided into two globes. One of the globes is slightly 

 larger than the other and presents fewer and smaller granules. The 



