62 THE MENDEL JOl RNAL 



from the pure black parent have been the result. The 

 whiteness of the albino parent is temporarily lost 

 to view ; but it is not destroyed or swamped. It 

 exists, and under the appointed conditions which 

 Nature has determined and we have now learned it 

 will reappear, pure and unaltered. Its association 

 with blackness, in the processes of heredity, has not 

 altered it. Environment, even of this intimate kind, 

 has not changed it. For, if we cross the sex-cells 

 of the brothers and sisters of this first generation, we 

 find that two kinds of rabbits are produced, i.e., 

 black and albinoes. Blackness and albinism have 

 separated out again, perfectly distinct. There has been 

 no blending of these characters, but segregation of them. 

 We know that each member of the offspring in 

 the first generation which results from uniting the 

 sex-cells of a pure black rabbit with those of an 

 albino must have been compound individuals, because 

 each must have contained both blackness and 

 albinism. They are, with respect to these two 

 characters, impure individuals. We may call them 

 hybrids, or heterozygotes*. But the feature of 

 interest is that although they are impure, since they 

 carry blackness and whiteness, they are indistin- 

 guishable from the pure black parent which carried 

 blackness only. Something must have happened 

 to the albinism, since it does not manifest itself in 

 these hybrids. We are not sure what does happen 

 to it, but it does not, for our present purpose, very 

 much matter. We have got the fact that one of the 



* A term applied by Prof. Bateson. 



