ENDONOMIC SELECTION ILLUSTRATED. 63 



the lower classes of animals, largely physiological, with some coordi- 

 nated instincts; while in the case of man the power of adjustment is 

 very largely psychological, and in the case of the other classes of ani- 

 mals, above the lowest, physiological and psychological adaptations 

 constantly cooperate. The explanation of these inherited adapta- 

 tions of the humblest organism to climatic and other conditions in- 

 volving great fluctuations is, I think, to be found in the fact that they 

 or their ancestors were gradually introduced to these alternations, 

 and that selection has thus had an opportunity to work for countless 

 generations in producing the corresponding complex adaptations and 

 powers of accommodation. It may be granted that man and his 

 ancestors have consumed an equal succession of ages in attaining the 

 inherited intellectual constitution that fits him for his higher sphere, 

 without lessening our apprehension of the wonderful contrast between 

 man and all lower organisms, in his power to enter suddenly upon a 

 new set of conditions. This power is so great that man may suddenly 

 enter a new territory, furnishing not a single product that he can eat, 

 and by his art of agriculture so completely meet his needs that he 

 becomes a permanent settler without even subjecting himself to any 

 new form of selection. In other words, accommodation is in some cases 

 so complete that coincident selection is prevented. This suggests that 

 in some spheres of activity, coincident {that is, organic) selection, is less 

 liable to occur in man than in animals whose accommodation is less 

 complete. 



8. Endonomic Selection illustrated by Several Species of North American Birds. 



By means of accom,modation birds and beasts determine their rela- 

 tions to the environment, and so determine the kind of selection to which 

 they and their descendants are thereafter subjected. The choice of con- 

 ditions that have brought pleasant experiences and the avoidance 

 of those that have brought unpleasant experiences is a degree of 

 intelligence enjoyed by many species of animals, and is a form of 

 accommodation that may determine the mode of life and so deter- 

 mine the forms of selection. For example, the cliff swallow, rang- 

 ing over most of North America, has accommodated itself to the new 

 conditions introduced during the past two centuries by the occu- 

 pation of the country by house-building people. Except in a few of 

 the Western States, where the population is sparse and the houses 

 few, it has deserted the cliffs and taken up its abode under the eaves 

 of the houses, thus bringing itself into very close connection with man 

 and subjecting itself to some forms of selection which it might have 



