Chap. XXV. CORRELATED VARIABILITY. 329 



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

 inherited effects of use, and of the mutual action of part on 

 part, have been equally or more important. 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 by analogy, 

 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 

 fact 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 subsequent wear and tear of the augmented 

 muscles and bones would require an increased supply of 

 blood, and consequently increased supply of food ; and this 

 again would require increased powers of mastication, diges- 

 tion, respiration, and excretion. 



Colour as Correlated with Constitutional Peculiarities. 



It is an old belief that with man there is a connection 

 between complexions and constitution ; and I find that some 

 of the best authorities believe in this to the present day. 38 

 Thus Dr. Beddoe by his tables shows 39 that a relation exists 

 between liabilitj' to consumption and the colour of the hair, 

 eyes, and skin. It has been affirmed 40 that, in the French 

 army which invaded Bussia, soldiers having a dark complexion 

 from the southern parts of Europe, withstood the intense 



" less and less capable of producing our domesticated quadrupeds and 



" specific adaptations ; and remains birds. 



" fully capable only of maintaining 38 Dr. Prosper Lucas apparently 



" the general fitness of constitution disbelieves in any such connection ; 



" to conditions." This view that ' L'Hered. Nat.,' torn. ii. pp. 88-94. 



natural selection can do little in 30 ' British Medical Journal,' 1862, 



modifying the higher animals sur- p. 433. 



prises me, seeing that man's selection i0 Boudin, ' Gebgraph. Medicale,' 



har undoubtedly effected much with torn. i. p. 406. 



