THEORY OF EXTRAORDINARY BIRTHS. 259 



new species. He believes further that all species 

 arise somewhat in this way. He recognizes as the 

 foundation of these births an internal law presiding 

 over the action of every part of every individual 

 and of every organism as a unit, and of the entire 

 organic world as a whole. " By such a force from 

 time to time new species are manifested by ordinary 

 generation." A sudden extraordinary birth takes 

 place, and the animal thus born becomes the pro- 

 genitor of a new species. 



Such a theory would avoid most of the difficulties 

 enumerated in the preceding chapters. The diffi- 

 culty of geological time is evidently no longer of 

 any importance, since species appear suddenly. The 

 absence of transitional forms between existing 

 species, an absence which we have seen both among 

 fossils and living forms, is no longer so much of a 

 surprise, for the infinite number of transitional 

 forms assumed by the selection theory have not 

 existed if Mivart's view be true. The difficulty of 

 conceiving the rudimentary beginning of organs and 

 of understanding how organs could be built up by 

 minute stages is completely avoided. If it be con- 

 ceded, as Mivart believes that there is an internal 

 bond uniting animals and regulating their develop- 

 ment, there is an immediate explanation of serial 

 homology, and of the independent origin of similar 

 structures. Highly complicated organs no longer 

 become a trouble, since in these extraordinary births 

 considerable changes occur at once. Finally, the 

 difficulty of the elimination of variations by crossing 

 is largely done away with, since observations have 



