598 RICHARD GOLDSCHMIDT 



IV 



The situation which we face as the result of our experiments is 

 the following. First, we recognized that the different effects of 

 the same sex-factors in different combinations can be under- 

 stood only by assuming a quantitatively different action; or, ex- 

 pressed in concrete terms, that the active substances, which we 

 represent as factors, are present in different but typical quanti- 

 ties. Second, we were obliged to assume that these substances 

 are distinct for each sex. Third, we realized that in the action 

 of these substances a time factor is involved, which is definitely 

 proportional to the quantities of the factorial substances. From 

 these facts only one conclusion can at present be drawn : that the 

 sex-factors are enzymes (or bodies with the properties of en- 

 zymes) which accelerate a reaction according to their concentra- 

 tion. Now we understand the homo-heterozygosis or one-x- 

 two-x mechanism of normal sex-differentiation as well as the 

 strange facts of intersexuality. In the fertilized egg the enzymes 

 which govern the differentiation of the organism towards one 

 of the two alternatives, maleness and femaleness, are both pres- 

 ent. For the sake of convenience let us call them andrase and 

 gynase. The mechanism of sex distribution — i.e., through the 

 sex-chromosomes — results in the formation of two kinds of fer- 

 tilized ova, differing in the relative concentration of the two en- 

 zymes. The formula FFMm means that the gynase is present 

 in a higher concentration than the andrase, and the formula 

 FFMM for the male that the concentration of the andrase is 

 higher. The absolute concentrations are such that the con- 

 stant concentration of the gynase (in female heterozygosis) is 

 higher than one portion andrase and lower than two. And 

 higher concentration results in greater rapidity of reaction and 

 the more rapid reaction wins. 



It is known that in mixtures of different enzymes, every single 

 one reacts independently, provided that no interfering reaction- 

 product is formed. Would this fact not lead to the conclusion 

 that every animal ought to be a protandric or protogynic her- 

 maphrodite? Theoretically this. is certainly correct, although 



