MRWtN AS ECOLOGIST. 



31 



be stated to consist of all those customs, and all those diseases which 

 seem to be generated by a scarcity of the means of subsistence ; and all 

 those causes independent of this scarcity, whether of a moral or physical 

 nature, which tend prematurely to weaken and destroy the human 

 frame." 



The above brief quotation will be enough to show that this process 

 of ' * natural selection ' ' in the human race has nothing whatever to 

 do with the origin of specific characters. Whatever infants die of, it 

 is not that they are born with, or develop, " injurious bodily charac- 

 ters," or inadaptive variations, as Darwin supposed to be the case with 

 animals and plants. They die by "fortuitous" destruction, such as 

 diseases, inherited or acquired, or feebleness of constitution, &c. 

 but they never — i.e. amongst any fixed p.opulation — start a new race 

 by " favourable variations," as we shall see Darwin assumes in the, so 

 to say, classical passage on Natural Selection, quoted here from the 

 " Origin of Species by Means of Natural Selection." 



The following is what I call the locus classicus of the theory;*'' 

 " Can it be thought improbable, seeing that variations useful to man 

 have undoubtedly occun^ed, that other variations useful in some way 

 to each being in the great and complex battle of life should [sometimes, 

 first edition] occur in the course of many successive [thousands, first 

 edition] generations? If such do occur, can we doubt (rememberiag 

 that many more individuals are born than can possibly survive) that in- 

 dividuals having any advantage, however slight, over others, would have 

 the best chance of surviving and procreating their kind? On the other 

 hand, we may feel sure that any variation in the least degree injurious 

 would be rigidly destroyed. This preservation of favourable individual 

 differences f and variations, and the destruction | of [those which 

 are] injurious, I have called Natural Selection [or the Survival of the 

 Fittest] (wanting in the first edition). 



Darwin compares Natural Selection with that of horticulturists; 

 but they are not really comparable. In the garden man selects in- 

 dividual plants and destroys the rest ; but every one which he discards 

 would have grown equally well had it been left. Darwin substitutes 

 " injurious " — i.e. death-bringing — inadaptive variations to account for 

 the majority dying. The cause in reality is not in any want of adapta- 

 bility in the individuals, but the circumstances of the struggle for 

 existence with one another. But it often happens that one species 

 drives out another in one place ;*but the reverse may take place else- 

 where — e.g. " Carex arenaria in sand chokes those which in clay 

 choke it," as Professor J. S. Henslow observed in 1825. 



No material changes of importance were made in four editions of 

 the Origin. " The fifth appeared in 1869. In a letter to Victor Carus 

 in that year he says: " The new edition is only two pages at the end 

 longer than the old [first ?] . Many of the corrections are only a few 



* Origin, cf-c, sixth edition, p. 63. 



t In first edition " Variations," without " individual differences." 

 + In first edition, "Kejection." 



