Modification of Germinal Canslitulion of Organisms 147 



On August 25, 1906, another series of pullets of the same strains 

 were similarly operated upon, controls being saved as before. They 

 weighed about 750 gms. each, the white ones being slightly the heavier. 

 All did well after the operation. No marked differences in egg produc- 

 tion were found between the control and operated hens, nor in the 

 fertility of the eggs. The operated hens at the beginning of the laying 

 season were somewhat lighter than the controls. In other respects 

 no differences were observed in either the hens, eggs, or chicks. 



The eggs became fertile in two to four days after mating and on 

 cessation of mating the eggs became infertile in eleven to nineteen 

 days, the majority becoming so on the fifteenth day. Control hens 

 Bi and Wi) mated to the rooster of the same breed gave uniformly 

 black fetuses and chicks in the case of the black hen, and white fetuses 

 and chicks in the case of the white hen. 



The normal black chicks had grayish-yellow breasts and throats 

 and frequently the under surface of the tops of the wings was light 

 colored as well, but the plumage of the entire dorsal surface was always 

 solid black. The light-colored areas on the ventral surface were 

 uniformly black after the first moult. Occasionally a normal black 

 may retain one or several white feathers in the tip of the wing per- 

 manently, but this is of rare occurrence and such white feathers have 

 not been observed in any other situation. 



The normal white chicks were pure white to light buff when hatched, 

 but after the first moult they were always pure white. The black 

 hen (B2), carrying an ovary from a white hen (W2) mated to the white 

 rooster, gave about equal numbers of white and spotted fetuses and 

 chicks. (In all cases of very small white fetuses, spots may ha\'e been 

 overlooked.) 



The white hen (W2), carrying an ovary from a black hen (B,) 

 mated to the white rooster, gave white, black, and spotted fetuses and 

 chicks. The spotted ones outnumbered the others combined. 



The black hen (B2), carrying an ovary from a white hen (W.) mated 

 to the black rooster, gave ordinary black, and black fetuses and chicks 

 with white legs, in about equal numbers. In regard to the chicks from 

 this hen described as ordinary black, some doubt exists as to whether 

 the ventral light-colored area described for normal black chicks was 

 not lighter and greater in extent in all cases than in the normal chicks. 



