A PHYSIOLOGICAL CHARACTER. 23 



2. This point bears on the question of the occurrence of "physio- 

 logical states" and their relative frequency. The discussion of (1) 

 and (la) bears directly on this point. 



3. To the possible objection that the method of selection was 

 suited to the production of more vigorous strains in the plus and less 

 vigorous strains in the minus strains, the answer is that such a result 

 did occur to some extent in two of the lines, but it was not a cumu- 

 lative result and the differences in reproductive vigor were not 

 greater at the close than during the early part of the experiment. 

 These cases are discussed in detail in the analysis of the data for the 

 various lines. But, as is pointed out later, in those cases in which 

 reduced reproductive vigor did occur it was not causally associated with 

 differences in reaction-time. 



4. This question, as applied to the selection problem, is a 

 "leading " question. Its answer depends upon whether the differences 

 are germinal or purely somatic. In the vast majority of cases such 

 reaction differences as are encountered in these selection experiments 

 are probably purely somatic, and the effect of selecting such variants 

 is of course nil. Whether some of these reaction differences are due 

 to germinal modifications will be taken up in connection with the 

 experimental data considered in this publication. 



