230 



CLAUDE W. MITCHELL 



Although in these mass cultures, conditions could not, of course, 

 be definitely controlled, yet all ordinary factors, food, fluid me- 

 dium, temperature, mass stimulus, and metabolic products were 

 made as uniform as possible and the fact that but four of the 

 seven cultures produced males indicates the probability that no 

 marked factor of sex-determination was to be found in these 

 conditions. Two other conclusions may also be drawn from these 

 early mass cultures, namely, that the potentiality of male pro- 

 duction was present even in the all but exclusive parthenogenetic 



TABLE 1 

 Mass cultures derived from individuals of Series A and D^ 



1 Table 2 in article in Jour. Exp. Zool., vol. 15, no. 1, 1913 



