334 Problems of Organic Adaptation 



the beneficial responses of individuals, as Lamarckism as- 

 sumes, since they benefit the species at the expense of the 

 individual. 



The probabilities are distinctly favorable to these two 

 fundamental propositions of Darwinism. We know that 

 mutations occur in many directions, and that most of them 

 are not beneficial. We know that the more injurious they are 

 the earlier the individuals possessing them are eliminated. 

 There is an immense elimination of germ-cells ; among mam- 

 mals not one spermatozoon among billions ever fertilizes 

 an egg, and not one egg in thousands matures and is fertil- 

 ized; and while it must often happen that the fittest perish 

 along with the most unfit, still it is highly probable that on 

 the whole the germ-cells that are fertilized and begin to 

 develop are among the fitter. There is a large elimination 

 of embryos and larvse; among many animals thousands 

 perish for every one that survives; and again, it is most 

 probable that on the whole and in spite of individual excep- 

 tions it is the fitter that survive. Many young and sexually 

 immature individuals die for every one that arrives at sexual 

 maturity, and here also the survivors are in general the 

 fitter. There is thus an immense elimination of individuals 

 in every generation before they reach the period of repro- 

 duction, and most of this elimination is wholly unseen and 

 unknown by the casual observer of nature. 



On the whole, much of this elimination is discriminative ; 

 there is universal elimination of the most unfit and, in gene- 

 ral, survival of the better fitted. It is true that in many 

 catastrophes destruction is wholly indiscriminate and the fit 

 and unfit perish together. Even in the more usual forms of 

 elimination, it does not happen that in every generation and 

 in every individual instance the fitter survive and the less 

 fit perish; but if this happens in the majority of cases, it 



