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A. FEANKLIN SHULL AND SONIA LADOFF 



peared in the control line, only seven such days in the oxygen line. 

 On the other hand, there were nine days on which the control 

 line yielded ten or more male-producers, only three such days 

 in the oxygen line. The second of the above-mentioned dif- 

 ferences may be partly due to the greater absolute number of 

 male-producers in the control line; but if allowance be made 

 for this fact, the former difference becomes all the more striking. 



Fig. 1 Graphic representation of the proportion of male-producers, computed 

 for three-day periods, in the two lines recorded in tables 16 and 18. The light 

 curve represents the oxygen line, the heavy curve the control. The fluctuation 

 is less in the oxygen line. 



A further difference between the two lines is the existence of four 

 fairly distinct waves of male-production in the control line, 

 each separated from the others by periods of few male-producers. 

 Such a rhythm in the oxygen line is less distinct, or in part wanting. 

 These differences are all due to a more uniform distribution 

 of the male-producers over the families of the oxygen line, and 

 over the period of the experiment in the oxygen line, than in 

 the control. Thus, although the oxygen did not cause an in- 

 crease in the number of male-producers, it was not without its 

 effect upon male-production. 



