Il8 THE METHOD OF DARWIN. 



It would seem as if Galton's experiments had 

 proved the hypothesis false. Darwin, how- 

 ever, met the criticism, and slipped away from 

 the results by admitting that he would have 

 expected gemmules in the blood; but showed 

 that their presence there was no necessary part 

 of his hypothesis, because the latter applied 

 to the lower animals and to plants, which do 

 not have blood. 1 Darwin's modest defence of 

 his hypothesis swept away not only Galton's 

 experiments, but the possibility of proving or 

 disproving it. Lionel Beale remarked, sarcas- 

 tically, that it might still be possible to test it 

 by cutting out a mass of an animal's flesh, and 

 grafting in its place a piece from an animal of 

 another variety. 2 Darwin's rejoinder to Galton 

 was sound from the former's point of view. 

 But the hypothesis was incapable of definite 

 proof or disproof. There was no set of facts 

 left that could be appealed to as a test. A 

 good induction will not only be in harmony 

 with and bring under one point of view a host 

 of facts, but is likely to be supported by one or 

 more of the following lines of proof: (i) inde- 

 pendent direct evidence of the existence of the 

 cause involved in the induction ; (2) strong and 



1 Nature, April 27, 1871, Vol. III. p. 502. 



2 Nature, May u, 1871, Vol. IV. p. 25. 



