Structural variation in the nervous system in relation to behavior.

Abstract

Species-constant characters give illuminating data for the problem of heredity-environment relationship. Species differences result from differences in structure, generally in the nervous system. Evidence of species-constant structures and of interspecies and intraspecies differences is reviewed. Though evidence for correlation of structural variations with behavior differences is incomplete, it is not likely that further investigation of this neglected field will fail to substantiate and extend the evidence now available. "Generalizations concerning the relative significance of constitution and experience will rest upon an insecure basis" until the functional significance of structural variations is detd.