ON POPPIES 



In the animal world, for example, where tho 

 study of the heredity of color has been carried out 

 pretty extensively in recent years, there are inter- 

 esting combinations showing a somewhat more 

 complex character than any that we have hitherto 

 examined. We have seen that in the case of the 

 guinea pigs black pigment is dominant to white, 

 so that when a black guinea pig is mated with a 

 white one the offspring are black, but the recessive 

 trait of whiteness reappears in one in four of the 

 progeny of the second generation. 



But it appears that in these animals, and sim- 

 ilar ones that are subject to wide varation of color, 

 there are curious complexities of heredity, all of 

 which, however, so far as studied, fall within the 

 scheme of "Mendelian" transmission. 



Thus it is found that in the case of mice, for 

 example, whereas blackness of coat is dominant 

 over whiteness, just as in the case of the guinea 

 pigs' blackness itself may be overlaid, as it were, 

 and entirely obscured by the presence of factors 

 for gray coating, and it further appears that 

 yellow pigment may dominate the gray coat, as 

 well as the black. 



A further complication occurs in that an animal 

 that is neither yellow nor gray nor black may be 

 chocolate in color. And it is only in case this 

 color also is absent that the mouse will be white. 



[127] 



