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A MANUAL OF MENDELISM 



Professor Nilsson-Ehle found the differences among the 

 various grains very sHght. Thus it makes Httle difference 

 to the colour produced whether one, two, or all three 

 factors are operating. His statement of the case is as 

 follows : "It can be asserted that the differences in the 

 externally visible effects of the various units for the red- 

 grain colour are quite inconsiderable, and that in any case 

 nothing can be said as to a qualitative distinction : less 

 even than in the black coat-colour of the oat. . . . The 

 units produce only a slightly different depth of red." 



