482 



AUSTIN RALPH MIDDLETON 



It is 13.74 selections per line for the fast-selected 'slow' lines and 

 12.79 selections for the slow-selected 'fast' lines. Now the aver- 

 age difference of fission rate per line per day for the eighty days 

 of balanced selection immediately preceding the present experi- 

 ment was 0.25 generation per hne per day and as a result of the 

 fifty days of reversed selection this difference was wiped out and 



15 r 



10 — 



« J 



Fig. 11-a Polygon of the average number of generations per line per ten- 

 day period produced by the 'fast' and 'slow' sets of lines of Experiment 1-C 

 (balanced selection for 50 days after SO days of selection, 40 days of balanced 

 selection and 12 days of mass culture). The continuous line shows the averages 

 for the 'fast' set, the broken one the averages for the 'slow' set. The ordi- 

 nates are the averages per ten-day periods, the abscissae, the ten-day periods. 



Fig. 11-5 Curve of the difference in favor of the fast lines between the aver- 

 age number of generations per line per ten-day period produced by the 'fast' 

 and 'slow' sets of lines of Experiment 1-C during its five consecutive ten-daj' 

 periods of balanced selection after mass culture. The ordinates are the differ- 

 ences of the averages, the abscissae the consecutive ten-day periods. 



