A PHYSIOLOGICAL CHARACTER. 



37 



The mean reaction-times obtained in the tabulation by two- 

 month periods (tables 5 and 6) are used in the plotting of curves 

 (figure 2c), showing graphically the courses of the selection experi- 

 ment with Line 695. 



Table 7 gives in abbreviated form selection summaries of the 

 data for 695 plus and 695 minus by the larger periods (mostly year- 

 periods) into which it was divided in tables 5 and 6; it also includes 

 summaries and results of the " test series" and summaries for selection 

 data for three-month periods during which the test series were con- 

 ducted. In table 7, in the vertical column to the left, are indicated 



TABLE 7. Selection summary for Line 695. 



the periods covered by the various portions of the summary; succes- 

 sive columns to the right of this indicate the strain (whether plus or 

 minus); the generations of descent during the period under con- 

 sideration; the number of broods used in selection and in obtaining 

 the data; the average number of individuals per brood of those 

 tested; the total number of individuals tested in making selections; 

 the number of individuals moving to the negative end of the tank; 

 the number failing to respond to the extent of reaching either end of 

 the tank; the average minimum reaction-time; the average maximum 

 reaction- time; the mean individual reaction-time; standard deviation 



