TABOO AND GENETICS 63 



is shorter-lived. Overworking and other condi- 

 tions tending to produce large eggs and females 

 also throw white mutants and show other signs 

 of weakness. Old females lay larger eggs than 

 do young ones. These eggs produce more 

 females. They store more material, have a 

 lower metabolism and less oxidizing capacity 

 than do the earlier male-producing eggs. 



It would be unsafe to draw specific conclusions 

 about mammals from these bird and insect 

 experiments. Both the secretory action and 

 the chromosome mechanisms are different. The 

 quantitative nature of sex, and also the existence 

 of intersexual types, between males and females, 

 would seem to be general phenomena, requiring 

 rather slight corroboration from the mammals 

 themselves. We have such mammalian cases 

 as the Free-Martin cattle, and some convincing 

 evidence of intersexuality in the human species 

 itself, which will be reviewed presently. 



The notion of more " developmental energy " 

 or a higher metabolism in males is borne out 

 in the human species. Benedict and Emmes 

 (7) have shown by very careful measurements 

 that the basal metabolism of men is about 6% 

 higher than that of women. Riddle cites the 

 work of Thury and Russell on cattle to show 

 that a higher water value (as he found in the 

 pigeon eggs), associated with increased meta- 

 bolism, helps to produce males. 



