106 



THE AMERICAN NATURALIST [Vol. LV 



front the Lamarckian when he strives to resuscitate the 

 faith that is in him. 



The opponent of Lamarckism certainly shines as a dis- 

 concerting questioner. Moreover, he is clearly correct 

 in his contention that the idea of germinal continuity is 

 the simpler one, and probably the only tenable one, as 

 regards the inheritance of characters, once they have 

 been engendered. But thq crux of the whole problem 

 lies in the question, where do new characters come from? 

 According to the followers of the great biological theo- 

 rist, Weismann, not only do new heritable characters 

 originate in the germ, but a change which first appears 

 in the body can not in any way become incorporated in 

 the germplasm. Unquestionably, constitutional changes 

 in a germ-cell at any time may find expression as a new 

 or modified character in the subsequent organism which 

 comes from this germ. But while this is an obvious fact, 

 it gives no real explanation of the origin of the character 

 in question, since it tells us nothing about what induced 

 the constitutional change. Weismann regarded sexual 

 reproduction, the intermingling of two lines of germ- 

 plasm, as an important cause of germinal variation, but 

 our modem genetical studies indicate that this is prob- 

 ably not true. Dual ancestry, of course, makes possible 

 new^ arrangements of germinal constituents which reveal 

 themselves in new combinations of characters, but the 

 germinal antecedents of such combinations are unitary 

 in nature, and there is no evidence that sexual mixture 

 originates any new units. So the Neo-Darwinian, al- 

 though highly successful in pointing out the shortcomings 

 of Lamarck, has been little if any more successful in ex- 

 plaining satisfactorily how changes are initiated in the 

 germ-cell. Yet it is this very item of change, of varia- 

 tion, that is the real basis of evolution. 



Some selectionists ,*iTi1)ly assci t that new characters 

 arise as the result of spmitniifons changes in the germ. 

 What is meant by this.' .Just what is a spontaneous 

 change? No one has ever succeeded in telling us. And 



