PHENOMENA OF INHERITANCE 291 



double ones the cross between negro and white 

 would have only one set of these factors for 

 black color, as shown by the formula AB x ab 

 = A Bab; hence the color of the F x generation 

 is intermediate between that of the two par- 

 ents. In the F 2 generation there should be a 

 variety of colors ranging all the way from 

 white to black, though pure white or pure black 

 would be expected in only a small proportion 

 of the offspring. As a matter of fact it is 

 known that the children of mulattoes vary 

 considerably in color, and in some cases a child 

 may be darker or lighter than either parent, 

 which would indicate that segregation does 

 actually occur. It is very probable that this 

 classical case of "blending" inheritance is really 

 Mendelian inheritance in which two or more 

 factors for skin color are involved. 



Similar "blending" inheritance is found in 

 certain other cases where the parents differ in 

 form or size. Thus Castle found that when 

 long-eared rabbits were crossed with short- 

 eared ones the offspring have ears of inter- 

 mediate length, and in all subsequent gener- 

 ations the ear length remained intermediate 



