4 88 GENERAL BIOLOGY 



ceedingly complicated cell-arborisations. In them are 

 possible channels of intercommunication in number far and 

 away beyond the needs of an organism for the performance of 

 the acts that are connected with the inherited instincts of the 

 species. The potential nerve paths of the brain, are at 

 first of equal resistance; through them sense perceptions 

 may find their way and responses may wear their channels 

 until all the main highways become established in exper- 

 rience. 



The external world rains down its innumerable stimuli 

 upon the organism. Those stimuli that are related to 



experience have the 

 right of way, and de- 

 termine action. The 

 experiences that ac- 

 company action are 

 retrained in the organ- 

 ism to augment or 

 modify or inhibit fur- 

 ther action. Discrim- 

 ination between 



FIG. 273. The hand of a little girl. Stimuli imprOVCS With 



the varying of experience. Discernment of the relation be- 

 tween cause and effect follows, and this may determine choice 

 of action ; at first the choice is based on the expected immedi- 

 ate good or ill results; later, on the more far-reaching con- 

 sequences of the act. Morality comes in here. 



In both body and brain man is at birth far more poorly 

 equipped for the struggle for existence than any other 

 animal. He has no defensive armor to ward off attacks of 

 enemies. He has no formidable bodily weapons, teeth, 

 fangs, claws or horns, to make them fear him. He has no 

 equipment of inherited behavior sufficient to insure his 

 safety. His new born spontaneity of movement is confined 



