2i8 BREEDING 



etc." Now this is demonstrably untrue, and no one 

 familiar with. Mendelian phenomena ever made such 

 a statement. Pure and extracted forms are only 

 supposed to be identical in respect of 'particular 

 character or characters. 



For instance, the albinos which appeared in the 

 second hybrid generation of my experiment, though 

 to all appearances identical with the pure albinos, 

 proved themselves, when mated with waltzers, to be 

 very different from them in their breeding properties. 

 For amongst the offspring of extracted albinos mated 

 with waltzers there appeared pink-eyed and even 

 albino mice, forms which are never produced when 

 pure albinos are mated with waltzers ; and this fact 

 was hailed by objectors to the Mendelian theory as a 

 conclusive proof of the falsity of the doctrine of the 

 purity of the gamete. " We have met you on your 

 own ground," they declared, " and have defeated 

 you. Here were two albinos which ought, according 

 to your theory, to be identical. We tested the con- 

 tents of their germ cells according to your teaching, 

 and we have demonstrated that they are funda- 

 mentally different." 



But a familiarity with the Mendelian account of 

 reversion, to be given in the next chapter, will at 

 once explain how such a result could occur and be 

 in perfect accord with Mendehan theory as now 

 held. There were, in all probability, amongst the 

 albinos in my second hybrid generation three zygotic 

 types corresponding to the three zygotic types of 

 white-flowered peas in the second hybrid generation 



