Ftmcttonal Selection iii 



which many have pointed out as characterizing and differenti- 

 ating life. It characterizes the responses of the organism, 

 however low in the scale, to stimulations — even to those of 

 mechanical and chemical (physico-genic) nature. Pfeffer 

 has shown such a determination of energy toward the parts 

 stimulated even in plants. And in the higher animals it 

 finds itself reproduced in type in the nervous reaction 

 seen in imitation and — through processes of association, 

 substitution, etc. — in all the higher mental acts of intelli- 

 gence and volition. These have been developed phylo- 

 genetically as variations whose direction was constantly 

 regulated by this form of adjustment in ontogenesis. If 

 this be true, — and the biological facts seem fully to con- 

 firm it, — this is the adaptive process in all life, and this 

 process it is with which the development of mental life has 

 been in the main associated. 



It follows, accordingly, that the three forms of onto- 

 genetic modification distinguished above — physico-genetic, 

 neuro-genetic, psycho-genetic — all involve the sort of re- 

 sponse on the part of the organism seen in this circular 

 reaction with excess discharge ; and we reach one general 

 method of ontogenetic accommodation upon which organic 

 selection rests. It is stated above in another connection 

 in these words : "The accommodation of an organism to a 

 new stimulation is secured, not by the selection of this 

 stimulation beforehand (nor of the necessary movements), 

 but by the reinstatement of it by a discharge of the 

 energies of the organism, concentrated so far as may be 

 for the excessive stimulation of the organs (muscles, etc.) 

 most nearly fitted by former habit to get this stimulation 

 again (in which the ' stimulation ' stands for the condition 

 favourable to adaptation). After several trials the child, 



