THE PROBLEM: THE NODE Off ITS SOLUTION 27 



embryonic development is one of the very strongest 

 evidences of our lowly origin. 



Thus we have three sources of information for the 

 study of animal genealogy. First, the comparative 

 anatomy of all the different groups of animals ; second, 

 their comparative embryology ; and third, their palse- 

 ontological history. Each source has its difficulties or 

 defects. But taken all together they give us a geneal- 

 ogical tree which is in the main points correct, though 

 here and there very defective and doubtful in detail. 

 The points in which we are left most in doubt in re- 

 gard to each ancestor are its modes of life and loco- 

 motion, and body form. But these may temporarily 

 vary considerably without affecting to any great extent 

 the general plan of structure and the line of develop- 

 ment of the most important deep-seated organs. 



I have chosen a line composed of forms taken from 

 the comparative anatomical series. All such present 

 existing forms have probably been modified during 

 the lapse of ages. But I shall try to tell you when 

 they have diverged noticeably from the structure of 

 the primitive ancestor of the corresponding stage. It 

 is much safer for us to study concrete, actual forms 

 than imaginary ones, however real may have been the 

 former existence of the latter. And, after all, their lat- 

 eral divergence is of small account compared with the 

 great upward and onward march of life, to the right 

 and left of which they have remained stationary or re- 

 trograded somewhat, like the tribes which remained 

 on the other side of Jordan and never entered the 

 Promised Land. 



To recapitulate : Our question is the Whence and 

 the Whither of man. To this question the Bible gives 



