No. 541] INHERITANCE OF COLOR IN CATTLE 



19 



It has been many times demonstrated that a positive 

 determiner in a gamete of a simplex individual is not as 

 "pure" as one from a duplex individual; furthermore, 

 a soma developed from a zygote made up of a gamete 

 containing a positive determiner, and another char- 

 acterized by its absence, is not as strong in the char- 

 acter in question as one produced by two duplex parents. 

 Thus, Davenport 22 has shown that in mating dominant 

 white fowls with pigmented fowls there is often an "im- 

 perfection of dominance,' ' giving rise to some more or 

 less scattered pigmentation in F 1 ; this he demonstrated 

 experimental! y and. among other things, finds that 



And he concludes that — 



tor-Hthe factor of the strength or potency of the representative of the 

 given character in the irerm plasm. This is clearly a variable quantity. 

 If it is very potent we get a typically Mendelian result but if it is 



Thus the determiner for pigmentation in the black 

 Cochin seems to be more concentrated than the same 

 determiner in the black Minorca. Or is it possible that 

 the antibodv, although present in quantities theoretically 

 in excess of the amount necessary for complete inhibition, 

 fails to effect such inhibition completely for the same 

 reason that the analogous phenomenon, due to some 



