VARIATIONS IN POTENCY 



they do not reduce the whole art of breeding 

 to the production of new combinations of unit 

 characters through crossing. Selection is re- 

 quired also, not merely among different combi- 

 nations of unit-characters, but also among in- 

 dividuals representing the same combinations 

 selection is required of those possessing the 

 desired characters in greatest potency. The 

 further role of selection in evolution we shall 

 need to consider in a subsequent chapter. 



BIBLIOGRAPHY 



CASTLE, W. E., and LITTLE, C. C. 



1909. "The Peculiar Inheritance of Pink Eyes Among 

 Colored Mice." Science, N. S., 30, pp. 312-314. 



COUTAGNS, G. 



1902. "Recherches expe*rimentales sur 1'he're'dite' chez lea 



vers-a-soie." Bull Sci., 37, pp. 1-194, 9 pi. 

 MORGAN, T. H. 



1909. "Breeding Experiments with Rats." American 



Naturalist, 43, pp. 182-185. 

 DE VRIES, H. 



1901-03. "Die Mutationstheorie." Leipzig, Veit and Co. 



See also the Bibliographies to Chapters III., IV., and V. 



