2,7,8 Appendix A 



remarkable and so iinexplainable that certain German writers, 

 such as Driesch, have taken the ground that they spring from 

 the ultimate constitution of living matter and are incapable 

 of analysis. At the same time it has been recognized that 

 these adaptations are purely individual, transitory, or ontogenic, 

 leaving, for a long time at least, no perceptible influence upon 

 the hereditary constitution of the organism. What may be 

 called the ' traditional ' side of these adaptations impressed 

 itself strongly upon Professor James Mark Baldwin in his 

 studies of mental development, also upon Professor Lloyd 

 Morgan in his studies of instinct. The latter, moreover, was 

 one of the first among English selectionists to consider ' deter- 

 minate variation ' as a fixed problem which must be included 

 in any evolution theory. Thus, independently, Professors 

 Baldwin and Morgan and myself put together the facts of 

 individual adaptation with those of determinate variation into 

 an hypothesis which is in some degree new. The first illustra- 

 tion which I used was that of the creation of an ' arboreal 

 man ' out of any present terrestrial race by the assumption 

 of an exclusively tree life. This life would be profound in 

 its influences upon each generation producing what would be 

 pronounced by zoologists a distinct specific type. In course 

 of many thousand years such a type might become hereditary 

 by the slow accumulation of arboreal adaptive and congenital 

 variations. 



" Organic selection is the term proposed by Professor Baldwin 

 and adopted by Professor Morgan and myself for this process 

 in nature which is believed to be one of the true causes of 

 definite or determinate variation. The hypothesis is briefly 

 as follows : That ontogenetic adaptation is of a very profound 

 character. It enables animals and plants to survive very critical 

 changes in their environment. Thus all the individuals of a 

 race are similarly modified over such long periods of time that 

 very gradually congenital or phylogenetic variations, which 

 happen to coincide with the ontogenetic adaptive variations, 

 are selected. Thus there would result an apparent but not 

 real transmission of acquired characters. 



