732 



THE AMERICAN NATURALIST 



[Vol. XLV 



preliminary working analysis. The 4 ' sensible percent- 

 ages" that Pearson objects to also impel the most ardent 

 adherent of the pure gamete theory to discard the single- 

 unit color coat hypothesis and to seek the unit — however 

 great or small — that does behave in the expected fashion. 

 We must agree with the above criticism that the incom- 



to ignore; such percentages simply indicate that the 



Red Lady 6th 86626. Eed. 



Dam— Red Lady (Imp.) . Eed, little Whit 

 Dam's Dam— Roan Mary. Boon. 

 Dam's Sire— Cornelius 226511. Eed. 



ultimate unit, or unit-behaving group of characters, is not 

 isolated, and that besides gametic segregation there is 

 occasionally intra-zygotic reaction. The old hypothesis 

 then must be abandoned and another better fitting the 

 facts must be worked out. Among other things the be- 

 havior of the unit complex must be studied. Thus, if a 

 Shorthorn is crossed with an Angus, the pure gamete 

 theory does not lead us to expect a series of "blends" or 

 of one of the pure parental types in the F 1 generation and 



