CONCLUSIONS 133 



The light thrown by these considerations upon the differ- 

 ence in the histories of inherited characters in natural and 

 in domesticated races is of the utmost importance. It is 

 quite evident that in domesticated races the influence of 

 bi-parental reproduction is partly eliminated. Man generally 

 selects animals and plants to breed from which possess, in a 

 marked degree, the characters which he desires to perpetuate. 

 The characters selected by man need not be of any advan- 

 tage to the individual, and the normal action of bi-parental 

 reproduction is done away with. Thus in domesticated races 

 we find that natural selection, the necessity for adaptation, 

 and the normal action of bi-parental reproduction are all inter- 

 fered with, while in natural races these are the factors that 

 have influenced the variations always occurring in all kinds 

 of organisms, and that have brought about evolution. In 

 bi-parental reproduction, then, instead of a cause of pro- 

 gressive variations, we find an explanation of regressive 

 variations. It is by this means that all useless variations 

 are eliminated. The bulk of the characters of a new indi- 

 vidual must, under the influence of bi-parental reproduction, 

 be limited to those that are common to the race. Even 

 these tend to be eliminated unless they are preserved by 

 the continuous action of natural selection. All progressive 

 variations occurring in an individual tend to be eliminated 

 rapidly unless they are advantageous, in which case they 

 are preserved by natural selection. Hence it would seem 

 that very few characters are inherited from the parents and 

 immediate ancestors; on the contrary the overwhelming 

 bulk of characters appearing in any individual are the 

 heritage of the race, and are derived from comparatively 

 remote ancestors. 



