SOME PROBLEMS OF REGENERATION. 199 



IV. 



An examination of the literature of regeneration will show 

 that there is a widespread dogma that the power of regenera- 

 tion of a part is commensurate with its liability to injury. I 

 have been able to trace this belief back to Bonnet, who says 

 that it is possible that the number of times a worm can regen- 

 erate a new part is in proportion to the number of accidents to 

 which it is exposed during its life. Bonnet found it convenient 

 to propound this statement in order that the results of the 

 experiments on regeneration might be fitted into the inelastic 

 preformation theory. 



The modern preformationists avoid the difficulty in other 

 ways, as may be seen in Weismann's book on the Germ- 

 plasm. 



What is even more surprising is the fact that modern 

 Darwinians pretend to be able to "explain" the process of 

 reeeneration as the result of natural selection. None of the 

 writers have, so far as I know, taken the trouble to tell us 

 how an indefinite series of injuries to a part could at last make 

 that part "acquire" a power to regenerate in succeeding gen- 

 erations. Darwin does not discuss the point, and his more 

 enthusiastic followers can only state that those animals are 

 '* fittest " that regenerate. They fail to see that even on their 

 own assumption regeneration often takes place without relation 

 to the survival or non-survival of the animal, and at best the 

 only possible statement that can be made is that all forms have 

 died that have not had the power to regenerate, and this admis- 

 sion would show only too clearly that they cannot pretend to 

 offer any "explanation" of the process itself. Such a state- 

 ment is, moreover, in direct contradiction to a large number of 

 known facts, for all animals alive at the present time do not 

 possess this power of regeneration. It would surely be as use- 

 ful to man to be able to reproduce a new arm or leg as it is for 

 a salamander to regenerate its limb or for an earthworm its 

 tail ; and I cannot but feel assured that mankind will never 

 acquire the property of replacing his arms and legs by a minutely 

 graduated series of injuries combined with an inbreeding of the 



