584 THE WONDER OP LIFE 



germ-cell, utilises this complexifying tendency in a pro- 

 gressive diSerentiation of its own. Just as the same 

 chemical substance may crystallize in more than one way, 

 so, but more subtly, the germ-cell may experiment with 

 its architecture. The germ-cell is no ordinary cell, it is 

 a gamete, a condensed individuahty ; and just as an 

 intact organism, from Amoeba to Elephant, tries experi- 

 ments, so it may be that the implicit organism of the 

 germ-cell tries experiments — ^which we caU variations. 

 Such at least is our view of a great mystery. 



It seems, then, if we are reading the story of Evolution 

 aright, that a genius may be born like Minerva from the 

 brain of Jove. There is brusquely a new pattern, ' some- 

 thing quite original ', a mutation. It used to be a dogma : 

 Natura non jacit saltus, but evidences of Natura saltatrix 

 are rapidly accumulating. They spoke of life ' slowly 

 creeping upwards ' — ^but the Proteus leaps as well as creeps. 

 There is doubtless some progress by thrift, by adding one 

 to one to make a thousand, but it is beginning to be clear 

 that Nature gambles. The great steps in evolution were 

 probably made by grands coups, not by savings. Many 

 of them express new ideas, and it is difficult to see how a 

 new principle in organization could originate gradually. 



While modern biology lays more emphasis on what may 

 be called the organismal factor in evolution — what is 

 attainable by the creative experiments of the organism, 

 especially in the germinal part of its life — this is in no way 

 inconsistent with the Darwinian theory of Natural Selec- 

 tion, or Nature's sifting. The raw materials are the inborn 

 variations ; the internal condition of progress is their 

 heritabihty and their consistency with the rest of the 

 organism ; the external condition is the struggle for existence 



