THE DETERMINATION OF DOMINANCE. 33 1 



The question is, to what is this behavior and its varia- 

 bility due ? The older writers confused dominance with prepo- 

 tence, and the behavior was attributed to "strength," to the age 

 of the parents at the time they reproduced, etc. As far as I can 

 discover, the evidence for strength or age is anecdotal or very 

 questionable in character, and in a long series of experiments I 

 have been unable to get any evidence that age of the gametes or 

 parents signifies anything in hybrid behaviors. Whatever is 

 meant by strength no one can say, and to attribute behavior 

 which gives dominance and recessiveness to differences in strength 

 is meaningless. If by this "strength of germs" is meant energy 

 for growth and development, we must, in order to utilize any 

 such conception, know how much potential energy is stored in 

 each germ — what the kinetic output would be when two germs 

 were combined, and the increase or decrease of the kinetic output 

 by conditions surrounding or incident upon the energy of the 

 zygote. In other words, the friction of the developmental proc- 

 esses will vary and be as productive of resultant differences as 

 are initial differences in the endowment of potential germinal 

 energy, if such there be. Much more knowledge of germ-plasm 

 physiology and dynamics is necessary before germinal energy 

 can play any part in the explanation of hereditary behavior. 



It has not thus far been shown that staleness of the germ cells 

 is productive of any of the results which have been described. 

 We know that germ cells become stale and that fertilization be- 

 comes difficult or impossible, and since development is slow or 

 incomplete from stale germs it is possible that when germ cells 

 that are stale are combined with those that are not, one or the 

 other may dominate in the cross. I have attempted many ex- 

 periments along this line, but thus far without any concrete evi- 

 dence that staleness in itself is productive of any result. 



In the present series of experiments there were involved in 

 the elytral stripes of one parent: 



1. Capacity to produce a substance capable of being oxidized 

 to form colored compounds. 



2. Capacity to produce an enzyme capable of oxidizing this 

 substance. 



In the other parent: 



3 . No capacity to produce either one or the other of the above. 



