CONCLUSIONS AND SUGGESTIONS 175 



tions, the only conclusion justified by the facts seems 

 to be that a decrement must exist in normal transmission, 

 but is much less marked, and the range of transmission 

 is therefore much greater, than under depressing con- 

 ditions. Undoubtedly in the higher animals the range 

 of transmission is very much greater than the limits of 

 the individual body, for the size of the individual in 

 these forms is limited by other factors than the range 

 of dominance (see pp. 46, 47, 151), but that transmission 

 without decrement occurs is far from being demon- 

 strated and, as I have endeavored to show, there is 

 much evidence against such a view. 



It is also a highly significant fact that the nervous 

 system, which is the chief conducting organ of the body 

 in those forms which possess it, develops in a definite 

 relation to the axial gradients. The dominant region 

 of the nervous system appears in the apical region of 

 the major axial gradient, and at other levels of the body 

 which contain the central nervous system it represents 

 the region of highest metabolic rate in the minor gradi- 

 ents. If the unity of the organism depends primarily 

 upon transportation, there is no apparent reason why 

 it should change to a unity depending on transmission 

 or why the dominant region of the central nervous 

 system should arise in the dominant region of the 

 primitive individual. If, however, organic unity is funda- 

 mentally and from the beginning dependent upon trans- 

 mission, the general plan and arrangement of the nervous 

 system are very evidently the expression in specialized 

 structure and function of the primary unity and relation 

 which was the starting-point of individuation, and domi- 

 nance or control by nervous transmission is merely 



