PROVOCATIVE BIOLOGICAL THEORIES 85 



may be. If, for example, a fertilized egg shows an X 

 chromosome, which, we know from previous experimen- 

 tation, causes femaleness, a chromosome bearing the de- 

 terminer for maleness also is present in that same fertil- 

 ized egg. He holds this statement to be true even though 

 that chromosome may not yet have been discovered, and 

 it is the metabolic struggle between the two which de- 

 termines the sex as well as all other characteristics of 

 the individual. If the metabolic rate of the X chromosome 

 is 100 per cent, then a 100 per cent male will result, while, 

 if the metabolic rate of the X chromosome is but 90 per 

 cent, then the metabolic rate of the opposing chromosome 

 (which we may not yet have discovered) is, of course, 10 

 per cent, resulting in a creature not 100 per cent male. 

 Such a creature, although a male, will have some female 

 characteristics. The theory holds thus, that such varia- 

 tion in the rate of metabolism may continue to a point 

 where the rate may approximate a 50-50 level. Since, 

 however, sex has but two alternatives, one cannot obtain 

 a perfect 50-50-level individual. In characteristics aside 

 from sex, such a percentage may be possible. The theory 

 really seems to explain many of the intersexual stages, 

 and may furnish an explanation of those characteris- 

 tics which do not seem to obey the Mendelian law of 

 dominance. 



The Theory of Plasmogeny. A. L. Herrera, of Mexico 

 (1921), not satisfied with seeking a unity in the realm of 

 living things, has attempted to find a broader unity un- 



