WEISMANN'S THEORY OF THE GERMPLASM 89 



is this : they reflect the characters of the adult 

 upon the undivided egg, and so people that sphere 

 of yolk with a system of tiny particles, corresponding 

 to the parts of the adult, qualitatively and in spacial 

 relations. But in this method of thinking, it is left 

 out of count that the egg is an organism which 

 multiplies by division into numerous organisms 

 like itself, and that, in each stage of the develop- 

 ment, it is only by the mutual action of all these 

 numerous elementary organisms that the develop- 

 ment of the whole organism slowly proceeds.' 



Weismann himself, in a discussion of the pan- 

 genes of De Vries, has partly shown that one 

 cannot assume the existence in the cell of material 

 particles that are the bearers of qualities foreign to 

 the nature of a cell and transcending it. In refer- 

 ence to the attempt to explain zebra-striping by 

 pangenes, he says (Germplasm, English edition, 

 p. 16) : ' There can be no "zebra-pangenes," because 

 the striping of a zebra is not a cell character. There 

 may perhaps be black and white pangenes, whose 

 presence causes the black or white colour of a cell ; 

 but the striping of a zebra does not depend on the 

 development of these colours within a cell, but is 

 due to the regular alternation of thousands of 



o 



black and white cells arranged in stripes.' Again 

 (p. 17), he says: ' The serrated margin of a leaf, 

 for instance, cannot depend on the presence of 

 " serration-pangenes," but is due to the peculiar 

 arrangement of the cells. The same argument 

 would apply to almost all the obvious " characters ' 

 of the species, genus, family, and so on. For 



