54 Hypothetical Bearers of Specific Characters 



grand-child four kinds of germ-plasms.^^ In the children 

 of the first sexually produced generation there will be only 

 one-half of the original amount of the two kinds of germ- 

 plasm, in the grand-children only one quarter. In every 

 succeeding generation the germ-plasm will consequently 

 consist of a larger number of unlike units, the so-called 

 ancestral plasms. But this can only continue until the 

 number of the ancestral plasms has reached that of the 

 smallest units of the entire hereditary substance. These 

 units, originally quite alike, are so no more, but each 

 possesses the tendency to transmit, under given condi- 

 tions, to the new organism, the totality of the character- 

 istics of the respective ancestors. 



If now sexual propagation takes place in a species 

 with this kind of compound germ-plasm, (and all living, 

 sexually differentiated species must obviously have 

 reached this stage long ago), a further multiplication of 

 the ancestral plasms within the germ-plasm can no longer 

 continue. Therefore the number of the ancestral plasms 

 must be reduced from time to time. In the separation 

 of the polar bodies from the ^gg before fertilization, he 

 sees a process, the result of which is just this reduction.^" 



This reduction in the tgg of the number of hered- 

 itary particles, as Weismann calls them, is obviously a 

 necessary consequence of the original assumption of the 

 uniformity of the germ-plasm. It is very instructive that 

 two such prominent thinkers as Spencer and Weismann, 

 starting from the same hypothesis, have arrived at an 

 ancillary hypothesis which is intrinsically the same. One 

 may well conclude from this that whoever does not wish 



21 Weismann, A. Ueher die Zahl der Richtungskorper, p. 30. 

 1887. 



22Loc. cit. p. 32 ff. 



