A PHYSIOLOGICAL CHARACTER. 



51 



effect of selection within this line. However, the actually smaller 

 difference in mean reaction-times during the last year as compared 

 with the preceding year does not lend support to this supposition, 

 and the same-day-brood data for the last longer period are in oppo- 

 sition to an effect of selection, so that a result of selection within 

 Line 691 must be considered very questionable. 



Obtaining the data for reproductive vigor (from the daily 

 laboratory notes) is laborious and was not done for Line 691 and a 

 number of the other lines in which there was obviously no effect of 

 selection or in which the results were inconclusive. 



The parallel effect of broad environmental influences upon the 

 reaction-time means for the two strains is shown in the curves 

 (figure 4) for the two strains, they in a general way following the 

 same course. 



Figure 4. — Line 691. Reaction-time curves. 



Line 711. 

 Tables 15, 16, 17, and 18 and figure 5 present the data for Line711. 



Table 15. — Selection data summarized by two-month periods for Line 711 plus. 



