PHYSIOLOGICAL DOMINANCE 89 



regions of the minor axes. For these reasons the experi- 

 mental investigation of dominance and subordination 

 in relation to the minor axes is variously complicated 

 and limited in different cases. Nevertheless, the funda- 

 mental similarity of the different directions of order in 

 the individual is indicated by various lines of evidence, 

 and there are no grounds for hesitation in extending to 

 the minor axes general conclusions reached concerning 

 the major axes. 



THE EXPERIMENTAL MATERIAL 



Reproduction can be induced experimentally in the 

 plants and many of the lower animals by the isolation 

 of pieces and in various other ways. These experimental 

 reproductions, when properly controlled and analyzed, 

 constitute invaluable material for study of the problem 

 of the individual, for it is often possible to increase or 

 decrease dominance and so to extend or decrease its 

 range, to alter the conductivity of protoplasm, to 

 determine the elimination of old and the establishment 

 of new metabolic gradients, and in these and other 

 ways to control the process of individuation to some 

 extent, and to determine the results of such control. 



Most plants and many of the lower animals give 

 rise to new individuals by division, budding, and other 

 agamic processes, and the new individuals thus formed 

 often remain organically connected and give rise to a 

 composite individual, such as a tree among plants or a 

 hydroid colony among animals. In such reproductions 

 definite and orderly space or distance relations are 

 observable, which themselves suggest the existence of a 

 limited range of dominance. The occurrence of division 



