82 THE EIDDLE OF THE UNIVERSE. 



particular). If the success of my General Morphology 

 was far below my reasonable anticipation, that of The 

 Natural History of Creation went far beyond it. In a 

 period of thirty years nine editions and twelve different 

 translations of it have appeared. In spite of its great 

 defects, the book has contributed much to the popu- 

 larisation of the main ideas of modern evolution. 

 Still, I could only give the barest outlines in it of my 

 chief object, the phylogenetic construction of a natural 

 system. I have, therefore, given the complete proof, 

 which is wanting in the earlier work, of the phylo- 

 genetic system in a subsequent larger work, my 

 Systematic Phytogeny (outlines of a natural system of 

 organisms on the basis of their specific development). 

 The first volume of it deals with the protists and 

 plants (1894), the second with the invertebrate 

 animals (1896), the third with the vertebrates (1895). 

 The ancestral tree of both the smaller and the larger 

 groups is carried on in this work as far as my know- 

 ledge of the three great "ancestral documents" — 

 palaeontology, ontogeny, and morphology — qualified 

 me to extend it. 



I had already, in my General Morphology (at the 

 end of the fifth book), described the close causative 

 connection which exists, in my opinion, between the 

 two branches of organic evolution as one of the most 

 important ideas of transformism, and I had framed a 

 precise formula for it in a number of " theses on the 

 causal nexus of biontic and phyletic development " : 

 " Ontogenesis is a brief and rapid recapitulation of phylo- 

 genesis, determined by the physiological functions of 

 heredity (generation) and adaptation (maintenance)." 

 Darwin himself had emphasized the great significance 

 of his theory for the elucidation of embryology 



