A PHYSIOLOGICAL CHARACTER. 



47 



Table 11. — Selection summary for Line 689. 



periment with this line in July 1913, the mean for the plus strain 

 was 295.1 seconds and for the minus 255.1 seconds. The difference 

 was +40.0 ±10.5 seconds, 3.71 times its probable error. There 

 was only one same-day brood^ for the four-month period, but there 

 were ten same-day broods during the later year-period. For these 

 same-day broods likewise the reaction-time for the minus strain was 

 lower than for the plus strain, but the difference was only 3 seconds 

 (table 12). 



It is an interesting fact that in this line, in opposition to selec- 

 tion, the minus strain persistently (except for 1 two-month period, 

 see table 10) maintained a lower reaction-time than the plus strain. 

 This difference, while not large for the greater part, is so general 

 that it can scarcely seem to be merely coincidental. The same-day 

 broods (table 12) show the minus broods with a smaller reaction- 

 time, but for the only significant group of these the difference is so 

 slight (3 seconds) as scarcely to be suggestive. 



^ For this pair of very small broods the mean of the plus strain was 163 seconds greater 

 than that for the minus strain. 



