A Test of the Metabolic Theory of Sex. 



9i 



of the table has therefore been constructed to eliminate those 

 unrepresented experiments. 



The table supplies a summary of the chief data obtained 

 concerning sex. It will be understood that the sex of many em- 

 bryos which were killed, and even of some which survived treat- 

 ment but died too soon thereafter, could not be ascertained. 

 It is clear that embryos which survive treatment with increased 

 oxygen are about equally capable of completing the remainder of 

 their embryonic development (hatching) regardless of sex. Per- 

 haps the ability to "hatch," after proved survival, should not be 

 considered as within the range of effects of treatment; but these 

 data are given. The quite different sex ratios obtained from the 

 increased oxygen experiments (129.6 & c? : 100 9 9) and from 

 the decreased (99.1 c^cf : 100 9 9) is perhaps good evidence that 

 the large number of killed and "unsexed" embryos of the first 

 group contained disproportionate numbers of females, while the 

 killed embryos of the second group probably included more males. 

 The sex ratio from embryos subjected to cooling is of such quantity 

 as to leave it a matter of doubt as to whether the killed and "un- 

 sexed" embryos differed in sex ratio from the survivors. This 

 ratio nevertheless markedly differs from that obtained from 

 increased oxygen. The known sex of the killed and of the sur- 

 vivors of this group also indicate clearly that the advantage here 

 rests with the females. 



The results are not wholly decisive but give some evidence 

 that sex is also a factor in survival; further, that it is the males 

 which best survive increased pressures of oxygen and females 

 which best survive decreased pressures and cooling. Nearly 

 all of the possible comparisons give the above result. The few 

 figures which are opposed or seem questionable are placed in 

 italics in the table. 



