VARIATION AND HEREDITY 141 



hereditary qualities are carried by represent- 

 ative particles in the germ-cells, we can in a 

 measure understand the origin of the kind 

 of variation referred to; for extraordinarily 

 intricate permutations and combinations go 

 on in the microcosm of the germ-cells. 

 Particularly in the process of maturation is 

 there what we might call a shuffling of the 

 cards even a throwing away of half of the 

 pack. In fertilization, again, paternal and 

 maternal contributions form a new unity. 

 Perhaps there may be, as Weismann sup- 

 poses, a struggle between rival hereditary 

 items. 



But there seems to be another kind of 

 variation, qualitative rather than quantita- 

 tive, substantive rather than architectural, 

 when something distinctively new appears. 

 What can be said as to their origin? Weis- 

 mann has suggested that the oscillations and 

 changes in the blood and other nutritive 

 fluids may stimulate the germ-plasm to a new 

 departure. It may also be that important 

 changes in the environment may saturate 

 through the body and provoke the germ- 

 plasm to vary. There are other :< may 

 he's." 



With all recognition and appreciation of 

 the work and thought above summarized, 

 we cannot but think that the secret of varia- 



