282 HEREDITY AND ENVIRONMENT . 



63 to 1. Consequently he concludes that while 

 the red color of wheat grains is usually due 

 to one factor for red, it may in some cases be 

 due to two or even three factors; notable de- 

 partures from expected ratios may thus be 

 explained. 



Blending Inheritance 



But the most serious objections whicn van 

 be presented against the universality of the 

 Mendelian doctrine are found in phenomena 

 of "blending" inheritance. In some instances 

 contrasting characters of parents appear to 

 blend in offspring and even in the F 2 and in 

 subsequent generations the descendants remain 

 more or less intermediate between the par- 

 ents. One of the best known illustrations of 

 this is found in the skin color of the mulatto 

 which is intermediate between the white parent 

 and the black one, and even in the F 2 and in 

 subsequent generations mulattoes do not usu- 

 ally, if ever, produce pure white or pure black 

 children, though the children of mulattoes show 

 considerable variation in color. Here there is 



