71 I 



THE AMERICAN NATURALIST 



[Vol. XLV 



Hypothesis. — There are two groups of genetically inde- 

 pendent sets of hairs intermingled to make up the Short- 

 horn color coat. One set is alternatively 11 positive 

 white" (W) and red (R), in which the white is dominant 

 and the red recessive; the other set is alternatively red 



Dam— Double Aconite 2d. Vol. 53, p. 563. Bed. Sire— Whitehall Marshall 209776. Boon. 

 Dam's Dam— Double Aconite. Bonn. Sire's Dam— Imp. Missie 167th. Boon. 



Dam's Sire— Godoy 115575. Bed. Sire's Sire— Whitehall Sultan 163573. Whi 



specific antibody existing in the zygote in small quan- 

 tit'u-s, retarding or inhibiting the ontogenesis of the 

 determiner for ingmentation. The same body existing 

 in larger quantities reacts with and destroys the deter- 

 miner for pigmentation, causing recessive or albinic 

 white. 



The dominant white of the Shorthorn is doubtless de- 

 rived from the Romano-British cattle, which it is generally 

 conceded entered into the Shorthorn make-up, which ele- 

 ment is to-day represented by the ' ' Park Cattle. ' ' They 



