84 THE RIDDLE OF THE UNIVERSE. 



palaeontology, Huxley proved that the " descent of 

 man from the ape" is a necessary consequence of 

 Darwinism, and that no other scientific explanation 

 of the origin of the human race is possible. Of the 

 same opinion was Carl Gegenbaur, the most distin- 

 guished representative of comparative anatomy, who 

 lifted his science to a higher level by a consis- 

 tent and ingenious application of the theory of 

 descent. 



As a further consequence of the " pithecoid theory " 

 (the theory of the descent of man from the age) there 

 now arose the difficult task of investigating, not only 

 the nearest related mammal ancestors of man in the 

 Tertiary epoch, but also the long series of the older 

 animal ancestors which had lived in earlier periods of 

 the earth's history and been developed in the course 

 of countless millions of years. I had made a start 

 with the hypothetical solution of this great historic 

 problem in my General Morphology ; a further develop- 

 ment of it appeared in 1874 in my Anthropogeny (first 

 section, Origin of the Individual ; second section, 

 Origin of the Race). The fourth, enlarged, edition of 

 this work (1891) contains that theory of the develop- 

 ment of man which approaches nearest, in my own 

 opinion, to the still remote truth, in the light of our 

 present knowledge of the documentary evidence. I 

 was especially preoccupied in its composition to use 

 the three empirical "documents" — palaeontology, 

 ontogeny, and morphology (or comparative anatomy 

 — as evenly and harmoniously as possible. It is true 

 that my hypotheses were in many cases supplemented 

 and corrected in detail by later phylogenetic research ; 

 yet I am convinced that the ancestral tree of human 

 origin which I have sketched therein is substantially 



