No. 627] 



ADAPTATION 



347 



either total or fractional development as a result. It 

 does not seem unlikely, therefore, that in every case of 

 regeneration the control of the ''organism as a whole" is 

 opposed, more or less successfully, by the specific growth 

 tendencies of the various cells and tissues from which 

 restitution proceeds. These might, in consequence, bring 

 about the "autonomous" production of a wholly mis- 

 placed part.^*' Thus the phenomena of "heteromorpho- 

 sis" should seem to offer no insuperable obstacle to the 

 view^s herein set forth. 



Applied to the ordinary phenomena of regeneration, 

 say to the restoration of an amputated limb, or even the 

 lens of an eye, this hypothesis of achievement through 

 experimentation would seem to make no impossible de- 

 mands upon our imagination. We need only suppose 

 that the absence of the missing part serves as a stimulus 

 to varied and undirected metabolic activities, that such 

 of these as serve to restore the normal condition tend to 

 be continued and that growth equilibrium (absence of 

 stimulus to growth) is not normally attained until the 

 missing part is restored. The case would seem to be not 

 very different from that of an animal finding its way out 

 of an unfavorable environment. In both instances we 

 may suppose the organism to be in a condition of "un- 

 rest" until the end is achieved. This condition may or 

 may not be conceived in psychical terms. If so con- 

 ceived, the notion would be philosophically legitimate, 

 though scientifically unnecessary. 



When, however, we consider Driesch's crucial case of 

 the development of an entire organism from an em- 

 bryonic fragment, the matter is admittedly far less con- 

 ceivable. For this fragment has retained nearly or 

 quite the same potentialities as the entire egg or embryo, 

 in that its career of multiplication and growth is brought 



19 This explanation of heteromorphosis is, I think, quite in harmony with 

 bv.IIolmeg (op. cit., pp. 302-303). 



