CHAPTER II 



EVIDENCES OF EVOLUTION FROM ANATOMIST, 

 EMBEYOLOGIST AND PHYSIOLOGIST 



Three Foundations of the Doctrine of Descent Homo- 

 logies New Organs from Old Classification Vestigial 

 Structures The Recapitulation Doctrine. Experi- 

 mental Evolution Direct Evidence of Blood-relation- 

 ship Man as Transformist. 



THREE FOUNDATIONS OF THE DOCTRINE OF 

 DESCENT. The general theory of organic 

 evolution for so long conveniently called the 

 ** doctrine of descent " has a tripod basis. 



(a) It rests, as we have seen, on definitely 

 ** historical " evidence on what can be 

 actually proved in regard to ancestry. Thus 

 recent discoveries have made the lineage of 

 the elephant convincingly clear, equalling, if 

 not surpassing in evidential value that of the 

 horse itself. 



(b) It rests also upon anatomical evidence, 

 on the disclosure of structural resemblances, 

 often beneath a mask of functional differences, 

 which are in many cases so intimate, so 

 thoroughgoing, so detailed, that it is impossible 

 to doubt that they spell affiliation. 



(c) It rests thirdly upon embryological 

 evidence, for the individual development 



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