404 THE ASCENT OF TYPE. 



advantage, however slight, over those with whom he 

 competes in this Food-scramble or struggle for exist- 

 ence, he will certainly survive ; and if he survives, then 

 some one else, so gentle Nature orders it, must die. 

 This Law of competition becomes itself a Force by 

 developing slight variations along lines of utility into 

 widely different and specific forms. 



But how is it that animals of the higher type pre- 

 vail ? Why should species, with a tendency towards 

 a complicated structure, generally triumph over simple 

 forms ? The reason appears to be this, that whenever 

 a change takes place it is almost invariably a change 

 towards complexity. Now it is an ascertained law 

 that animals are invigorated by a slight change; they 

 are therefore improved by an approach towards com- 

 plexity. Let us take the most mysterious of all pro- 

 gressive operations — the division of the sexes. The 

 hermaphrodite can fertilise itself, but its organs are so 

 arranged that it can be fertilised by another individual, 

 the wind or the water acting as the go-between. The 

 offspring of such separate unions are always more 

 vigorous than the home-born progeny of the herma- 

 phrodite. The latter are therefore killed off by means 

 of the struggle for existence, and sexual union, at first 

 the exception, becomes the rule. Just as a body of 

 artisans can do more work and better work when each 

 man devotes his whole life to a single department of 

 the craft, so it is good for the animal that division of 

 labour should be established in its structure ; that in- 

 stead of the creature being its own mouth, its own 

 stomach, its own organ of excretion, reproduction, and 

 locomotion, it should be divided into separate parts, 

 one of which moves it, another part takes the food, 

 another part chews, another part digests, another part 



