EVOLUTION 



481 



Table of Collateral Heredity 



problem of cross heredity (see p. 454)- It suggests that 

 if we multiply the coefficient of direct heredity by the 

 organic correlation of the two characters under discussion, 

 we shall obtain the coefficient of cross heredity.^ Thus .4 

 times the correlation between stature and forearm in man 

 would give the degree of relationship between the fore- 

 arm in a man and the stature of his brother. Measure- 

 ments are now being made to test this apparently simple 

 law of cross heredity. 



§ 12. 



-On the Power of Selection to permanently modify 

 Types by the Establishment of Breeds 



The next most important point for our consideration 

 is the manner in which heredity can assist selection, 

 natural or artificial, in the establishment of breeds or in 

 the permanent modification of types. 



Now there are two distinct cases to be considered 

 here. In the case of artificial selection, pedigree stock, 

 and laboratory experiment, we may be acquainted with a 



1 The principle here stated depends upon a further assumption stated, 

 Royal Society Proceedings, vol. Ixii. p. 411. The cross inheritance from 

 stature in father and forearm in son, which I have determined for 1000 cases, 

 sensibly obeys this principle. 



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