ORIGIN OF ORGANIC FORMS 305 



yet by observing a whole series of slightly varying 

 transitional forms between a suckling and an old man, 

 by observing that all these beings vary before his eyes 

 though to a very small degree, and vary in one direction 

 only, i.e. become older, our imaginary being would come 

 to the conclusion that the child he sees before him will 

 in time become an old man, and that just as truly the 

 old man has also been a child in his time. Let us also 

 suppose that another similar imaginary being should 

 criticise this conclusion by saying : ' I maintain that a 

 grown-up man has never been a child, and will maintain 

 this statement until I see the transformation take place 

 before my very eyes, which, as a matter of fact, could 

 never happen.' Tell me, pray, who is in the right ? Is 

 it the one who reduces the whole of his experience to 

 terms of a strictly logical inference, or is it the other who 

 obstinately indulges in a kind of pseudo-philosophical 

 scepticism, repudiating both the testimony of experience 

 and the requirements of logic ? Yet this is exactly 

 the position of the two opposite camps with regard 

 to the question of species. Not only the life of a 

 single man, but even many generations are as nothing 

 when compared with the period of time necessary 

 for the formation of a new species ; yet scientists 

 who repudiate the immutability of species, seeing the 

 variability of organic beings and taking into con- 

 sideration the impossibility of establishing a difference 

 between a species and a variety, inevitably come to the 

 conclusion that species have arisen from varieties ; that 

 varieties are only consecutive steps towards the for- 

 mation of new species. 



However conclusive this method of proof may be, 

 there is no doubt that the actual observation of the 

 formation of new species would have been more 

 conclusive still. If species do vary, may they not 

 within the confines of history have varied so much 

 as to give rise to new species ? This cannot possibly 



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