DOMINANCE 



dominance depend? Why should black domi- 

 nate white rather than the reverse? 



In poultry, indeed, the relations are often 

 reversed, white dominating black. Why is 

 this? Several attempted explanations have 

 been made, but none of them is thoroughly 

 satisfactory. The one which has found wid- 

 est acceptance is this: In the dominant in- 

 dividual something is present which is want- 

 ing in the recessive. Thus, in the black guinea- 

 pig there is present some ferment-like body 

 or some ingredient of black which is wanting 

 in the albino. Accordingly, the black guinea- 

 pig forms pigment, a thing which the albino 

 can do only feebly or not at all. The distinc- 

 tive something of the black parent therefore 

 dominates a corresponding nothing of the 

 white parent. White fowls, on the other hand, 

 are not albinos. They have pigmented eyes. 

 Accordingly they do not lack the power to 

 form pigment, owing to the absence of some 

 necessary ferment or pigment ingredient. 



White guinea-pigs occur which are in a way 

 comparable vsdth white fowls. They look ex- 

 actly like albinos, except that their eyes are 

 5 53 



