INFLUENCE OF ENVIRONMENT 343 



hereditary characteristics of the transplanted 

 ova are in no wise changed by . the foster 

 mother. They removed the ovary from a pure 

 black guinea-pig and put it in the place 

 of the ovary of a pure white animal. After 

 recovery from the operation this white female 

 with the "black" ovary was bred to a pure 

 white male (Fig. 81). Three litters of off- 

 spring from these parents were all pure black 

 as shown in Figure 82. Although both parents 

 were pure white all the offspring of the FI 

 generation were black because they came from 

 "black" eggs and black is dominant over white. 

 The fact that these "black" eggs matured in 

 the body of a white female did not in the least 

 change their hereditary constitution. 



A still more intimate union takes place when 

 the dominant and recessive characters come 

 together in any zygote. These characters, or 

 rather the factors which determine them, may 

 be intimately associated in every cell of the 

 organism throughout an entire generation and 

 yet we may get a clean separation of these 

 characters in the next generation; in many 

 cases neither the dominant nor the recessive 



