424 



THE POPULAR SCIENCE MONTHLY 



Fig. 5. A black female Guinea-pig and her Young. 



Fig. 6. An Albino Guinea-pig, father cf black young, like those seen in Fig. 5. 



of this generation, one by one, with albinos, we find that on the average 

 two out of three of them will produce white offspring as well as black 

 ones, while the third one produces only black offspring. 



The scientific law which governs the inheritance of albinism, and 

 of other characters transmitted in a similar fashion, is known as 

 Mendel's law. It applies, apparently, to all cases of color-inheritance, 

 as well as to the inheritance of characters of many other sorts. Through 

 its operation new combinations of the peculiar characters of individuals 

 or of races can be obtained in the course of one or two generations. 

 Thus when a guinea-pig showing the two coat-characters seen in Fig. 

 9, dark and smooth coat, is mated with one showing the combination, 

 white and rough, Fig. 10, young are produced showing a wholly new 

 combination, dark and rough, Fig. 11. And if these young are at ma- 

 turity bred together, a fourth combination, white and smooth, appears 

 among their young, the grandchildren. See Fig. 12. Other grand- 

 children manifest the combinations seen, respectively, in the parents 

 and in the grandparents. By selection any one of these combinations 

 may be obtained in a pure race. 



Oftentimes a new combination of characters obtained through 



