CHAPTER V 



MENDELISM 

 1. METHODS OF STUDYING HEREDITY 



MODERN studies in heredity have been pursued princi- 

 pally in three directions : first, by microscopical ex- 

 amination of the germ-cells; second,, by statistical 

 consideration of data bearing upon heredity ; and 

 third, by experimental breeding of animals and plants. 

 In the present chapter attention will be directed to a 

 consideration of experimental breeding with reference 

 to hybridization, that is, breeding from unlike parents, 

 a process which Jennings characterizes by the expres- 

 sive phrase, "the melting-pot of cross-breeding." 



2. THE MELTING-POT OF CROSS-BREEDING 



Hybridization, or cross-breeding, as analyzed by 

 ^Galton (1888), results in one of three kinds of inherit- 

 ance, namely, blending, alternative, or particulate. 



Of these, blending inheritance may be called ,the 

 typical ''melting-pot" in which contributions from the 

 two parents fuse into something intermediate and dif- 

 ferent from that which was present in either parent. 

 Galton illustrated this process by the inheritance of 

 human stature in which a tall and a short parent pro- 



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