Successively Activated Specific Elements 155 



the face can be maternal and the eyes, in spite of that, be 

 entirely paternal in character ; the dimple which the father 

 had on his chin may be found again in the child, although 

 in the form of its face and nose it may resemble the 

 mother rather than the father." 125 



Let us note at the same time that the germ substance 

 of the fertilized egg must contain the anlagen of both the 

 paternal and maternal germ substance, and that the 

 former as well as the latter, since they correspond one to 

 another in pairs, tend to become active in pairs simulta- 

 neously or almost simultaneously, except in the cases 

 where they are of such nature as to be reciprocally 

 exclusive. 



Now if we suppose that the process may be of epi- 

 genetic nature, and if we suppose also that the different 

 anlagen of the germ substance becoming successively ac- 

 tive, are all located in one definite zone of the organism 

 from which they send forth their formative action, then 

 it is clear that the different points of the soma must 

 experience the determinative influence of the paternal and 

 maternal germinal anlagen at the same time. 



Consequently when the corresponding anlagen com- 

 posing each couple are quite identical, as will be the case 

 especially during the first stages of development and per- 

 haps also at subsequent stages more or less advanced, 

 then the two respective, determinative actions will be- 

 come fused into one, and there would result the exact 

 reproduction of the entirely similar characters which the 

 two parents possess in common. 



When on the contrary the corresponding anlagen com- 

 posing each pair are different, provided that they are not, 



126 Weismann : Das Keimplasma. P. 377. 



