Chap. XXV. CORRELATED VARIABILITY. 335 



male elk its present structure, yet it is probable that the inhe- 

 rited influence of use has played an equal or more important 

 part. As the horns gradually increased in weight, the muscles 

 of the neck, with the bones to which they are attached, would 

 increase in size and strength ; and these parts would react on 

 the body and legs. Nor must we overlook the fact that certain 

 parts of the skull and the extremities would, judging byanalo°y, 

 tend from the first to vary in a correlated manner. The increased 

 weight of the horns would also act directly on the skull, in the 

 same manner as, when one bone is removed in the leg of a 

 dog, the other bone, which has to carry the whole weight'of the 

 body, increases in thickness. But from the facts given with 

 respect to horned and hornless cattle, it is probable that the 

 horns and skull would immediately act on each other through 

 the principle of correlation. Lastly, the growth and subse- 

 quent wear and tear of the augmented muscles and bones 

 would require an increased supply of blood, and consequently 

 an increased supply of food; and this again would require 

 increased powers of mastication, digestion, respiration, and 

 excretion. 



Colour as Correlated with Constitutional Peculiarities. 



It is an old belief that with man there is a connexion between 

 complexion and constitution; and I find that some of the best 

 authorities believe in this to the present day. 34 Thus Dr 

 Beddoe by his tables shows -that a relation exists between 

 liability to consumption and the colour of the hair, eyes, and 

 skin It has been affirmed * that, in the French army which 

 invaded Russia, soldiers having a dark complexion, from the 



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