CHARACTERS IN HEREDITY 153 



but not so those of the second generation (F2) . 

 Among these thirty-two different classes may be 

 recognized, that is, thirty-two sorts which, though 

 all looking alike, produce each a different assort- 

 ment of young. These assortments are : — 



1. Gray only. 



2. Gray, and black. 



3. Gray, and white. 



4. Gray, black, and white. 



5. Gray, and yellow. 



6. Gray, black, yellow, and sooty. 



7. Gray, yellow, and white. 



8. Gray, black, yellow, sooty, and white. 



Eight other varieties produce the same sorts of 

 young as these eight respectively, but in addition 

 produce dilute pigmented ones of the same color 

 types, i.e. blue-grays as well as grays, blue as 

 well as black, cream as well as yellow, and pale 

 sooty as well as sooty. Sixteen other varieties 

 produce the same assortments of young as these 

 sixteen, but in addition produce animals spotted 

 with white in each of the several color types. 



The facts briefly stated are now before us. 

 We can distinguish among the second generation 

 gray rabbits thirty-two different kinds, all look- 

 ing alike but all breeding differently. Out of 

 this apparent chaos the Mendelian theory of unit 

 characters brings law and order; no other ex- 

 planation has been offered which makes anything 

 but chaos out of the situation. The number of 

 distinguishable classes, thirty-two, shows that 



