I 88 THE CAUSATION OF DISEASE. 



the most beautiful males during many generations. Speaking 

 of the method by battle, Darwin says : — 



" How low in the scale of Nature the law of battle descends I 

 know not : male alligators have been described as fighting, bellow- 

 ing, and whirling round, like Indians in a war-dance, for the 

 possession of the females ; male salmons have been seen fighting all 

 day long ; male stag-beetles sometimes bear wounds from the huge 

 mandibles of other males ; the males of certain hymenopterous in- 

 sects have been frequently seen by that inimitable observer, 

 M. Fabre, fighting for a particular female, who sits by, an appa- 

 rently unconcerned beholder of the struggle, and then retires with 

 the conqueror."* 



The Action of E independently of Selection. — We have seen 

 that the E is capable of modifying structure in a marked 

 degree, and that any of the variations thus induced may be 

 accumulated and intensified by selection, the organism thus 

 becoming, by indirect means, adapted to its E. Wherefore 

 Herbert Spencer speaks of this process as indirect equilibration. 



The E may, however, work marked and definite changes upon 

 a race, in the course of a few generations, altogether independently 

 of selection. This process the same writer terms direct equili- 

 bration ; while Darwin speaks of it as the direct and definite 

 action of the conditions of life. Thus, the woolly hair of the 

 negro is not the product of selection, but results from the 

 direct action of certain atmospheric conditions, and the 

 characteristic conformation of the true Yankee — his spare 

 form, high shoulders, pigmented skin, and more or less 

 hairless face, are evidently due to the action of his E, 

 independently of selection, natural or sexual. It is indeed 

 quite astonishing how rapidly the E may thus modify a 

 race ; any one practising among the poor of London may 

 very soon prove this for himself. It is very easy, for in- 

 stance, to distinguish between the crania of London and 

 country-born individuals, for the bones undergo considerable 

 change, even in the space of one generation. 



In considering this action of E independently of selection, 

 we must be careful to remember the very wide significance of 



* "Origin of Species," p. 101. 



