A PHYSIOLOGICAL CHARACTER. Ill 



5. Arbitrarily selecting the 6 periods of highest reproductive 

 indices for the plus strain, they have, as compared with adjacent 

 parts of the curve, a higher reaction-time twice, an intermediate 

 reaction-time once, and a lower reaction-time 3 times. The minus 

 strain for its 6 highest reproductive indices has a higher reaction- 

 time 4 times, an intermediate reaction-time once, and a lower reac- 

 tion-time once. The 5 periods of lowest reproductive indices for 

 the plus strain have, as compared with adjacent points in the curve, 

 a higher reaction-time 3 times and a lower reaction-time twice. 

 The similar periods for the minus strain have a higher reaction-time 

 in one case, an intermediate reaction-time in 3 cases, and a lower 

 reaction-time once. 



The comparisons under (4) and (5) show some evidence of a 

 relation between vigor and reaction-time in the plus strain, the mean 

 reaction-time more often varying in the direction anticipated, if 

 greater vigor is associated with greater promptness in reaction (and 

 hence lower reaction-time) than in the reverse direction. But with 

 the minus strain the differences are such as to indicate the reverse 

 relation, i. e., greater vigor associated with less promptness in re- 

 action (higher reaction-time). These small differences about neu- 

 tralize each other and lead one to conclude, from this portion of 

 the evidence, that there is probably no relation between vigor and 

 reaction- time. 1 



6. For the two-month period during which the minus strain 

 showed its greatest vigor (October November 1914) its mean reaction- 

 time was greater than at any other period except one, and much 

 greater than the average for the succeeding 5 periods, during which 

 its reproductive index was about 35 per cent lower. 



7. It is worthy of note that 4 of the 6 high points in the curve 

 of the reaction-times of the minus strain occur when the minus 

 strain was superior in vigor to the plus strain. This, if considered 

 alone, would seem to suggest a reverse relation between reproductive 

 vigor and reaction-time, a relation which would seem not to have 

 biological significance. 



8. Attention may be directed to the two-month periods during 

 which (even after the effect of selection appeared already to have 

 become established) the minus strain had a reaction-time approxi- 

 mating or lower than that for the plus strain. For the period June- 

 July 1914, during which the minus strain was on the average the 

 more reactive of the two, and the following two-month period during 

 which the minus strain was the less reactive by only 2 seconds, the 

 plus strain was markedly the more vigorous. For the February- 

 March 1915 period, when the minus strain was within 64 seconds 

 of the plus strain, the minus strain was slightly the more vigorous. 



1 These data, however, might be taken to offer slight corroboration of the puzzling results 

 obtained from the correlations based upon this data (see page 113). 



