ENDONOMIC AND COINCIDI-NT SELECTION CONTRASTED. 65 



Ponape, one of the Caroline Islands, the only substitute for mother's 

 milk known to the aborigines is the juice that exudes from the imma- 

 ture fruit-stalk of the eoeoanut tree when the end of the immense bud 

 is sliced off. In Japan, if a wet nurse can not be provided, sweet 

 extract of malt is used. In some lands mare's milk is used ; in some 

 ass's milk; and in others goat's milk, or cow's milk ; but all these are 

 somewhat deficient, unless modified and sterilized by the highest skill 

 of the physiologist and chemist. Any case of selection introduced and 

 protected from failure by accommodation is a case of "coincident {or 

 organic) selection."* 



10. Endonomic Selection and Coincident Selection Contrasted. 



Active (or endonomic) selection is due to powers enabling the organ- 

 ism to deal with the same environment in different ways. This 

 power is especially manifest when the organism is dealing in isolated 

 groups with the same conditions. Different methods arise: 



(1) Because the innate aptitudes of different individuals and groups 

 for dealing with the environment differ somewhat. This results in 

 aptitudinal selection. 



(2) Because the training, and, therefore, the habitudes, of different 

 individuals and groups, in dealing with the environment, differ some- 

 what. This results in habitudinal selection. 



(3) Because individuals with the same aptitudes and habitudes 

 may take up different methods of dealing with the same environment, 

 through the accidents attending their entrance on their new districts, 

 both in cases when these new districts all differ from the original home 

 in the same way and when all afford exactly the same conditions as the 

 original home. Shall we call this accidental selection? Or will some 

 one suggest some other term more suitable? 



Coincident (or organic) selection is due to the protection derived 

 from the discriminative and other accommodational powers of the 

 individuals, preserving the organism from extinction under the stress 

 of great and sudden change, either in the environment or in the rela- 

 tions of the members to each other, and thus giving time for the pro- , 

 duction and accumulation of variations that coincide with the accom- 

 modation in adapting the organism to the new conditions. 



Active (or endonomic) selection rests on "alternative methods of 

 adjustment to the same environment till the organism has adopted a 

 particular method of suiting itself to its conditions."^ 



* See Baldwin's Development and Evolution, pp. 95 and 173. 

 f This form of statement is quoted from Headley's Problems of Evolution, p. 

 149, where he is describing what he calls methods of evolution by natural selection. 



