112 DARWINISM AND HUMAN LIFE 



organism) by the entrance of the fertilising sperma- 

 tozoon whose chromosomes have also been reduced 

 by a half. In fertiUsation, at the beginning of 

 each new Ufe, there is an intricacy of combination 

 that may be likened to the making of a living 

 mosaic out of parental and ancestral contributions. 

 It may also be that in the making of the germ- 

 cells there is a segregation of antithetic qualities, 

 so that two different kinds of germ-cells result, 

 corresponding to the two sharply contrasted 

 parents. It may also be, as Weismann supposes, 

 that there is a struggle between rival unit-char- 

 acters in the penetralia of the germ-cells. In 

 any case, there is abundant opportunity for new 

 permutations and combinations. There are many 

 factors which may give the vital kaleidoscope a 

 twist. 



There is, however, another kind of variation, 

 when novel features appear, which are quaUtative 

 rather than quantitative, substantive rather than 

 architectural, in kind rather than in degree, and 

 more than mere rearrangements of previously 

 expressed unit characters. What can be said as 

 to their origin ? 



Weismann and others have suggested that 

 the stimulus to germinal variations comes from 

 the oscillations and changes in the immediate 

 surroundings of the germ-ceUs. They get their food- 

 supply from the body, and that food-supply is 

 liable to be somewhat variable. It may contain 

 a poison, for instance, which seriously shakes 

 the architecture of the germ-plasm at the very 

 start; but it may also contain some stimulus, 

 which provokes the living germ to a new de- 

 parture. 



