454 THE EVOLUTION OF LIFE. 



but demands many powers ; in the same .proportion do there 

 arise obstacles to the increase of any particular power, by 

 *^the preservation of favoured races in the struggle for 

 life/^ As fast as the faculties are multiplied, so fast does it 

 become possible for the several members of a species to have 

 various kinds of superiorities over one another. While one 

 saves its life by higher speed, another does the like by clearer 

 vision, another by keener scent, another by quicker hearing, 

 another by greater strength, another by unusual power of 

 endiu^ing cold or hunger, another by special sagacity, another 

 by special timidity, another by special courage ; and others by 

 other bodily and mental attributes. Now it is unquestionably 

 true that, other things equal, each of these attributes, giving 

 its possessor an extra chance of life, is likely to be transmitted 

 to posterity. But there seems no reason to suppose that it will 

 be increased in subsequent generations by natural selection. 

 That it may be thus increased, the individuals not pos8ess- 

 ing more than average endowments of it, mast be more fre- 

 quently killed off than individuals highly endowed with it ; 

 and this can happen only when the attribute is one of greater 

 importance, for the time being, than most of the other attri- 

 butes. If those members of the species which have but 

 ordinary shares of it, nevertheless survive by virtue of other 

 superiorities which they severally possess ; then it is not easy 

 to see how this particular attribute can be developed by 

 natural selection in subsequent generations. The probability 

 seems rather to be, that by gamogenesis, this extra endow- 

 ment will, on the average, be diminished in posterity — just 

 serving in the long run to compensate the deficient endow- 

 ments of other individuals, whose special powers lie in other 

 directions ; and so to keep up the normal structure of the 

 species. The working out of the process is here somewhat 

 difficult to follow ; but it appears to me that as fast as the 

 number of bodily and mental faculties increases, and as fast as 

 the maintenance of life comes to depend less on the amount 

 of any one, and more on the combined action of all ; so 



