298 The Study of Animal Life part iv 



motion, during which the matter passes from an indefinite 

 incoherent homogeneity to a definite coherent heterogeneity, 

 and during which the retained motion (energy) undergoes a 

 parallel transformation." He has given his life to establish- 

 ing this generalisation, and applying it to physical, biological, 

 psychological, and social facts. As to the factors in organic 

 evolution, he emphasises the change-producing influences of 

 environment and function, and recognises that natural selec- 

 tion has been a very important means of progress. 



Ernst Haeckel, Professor of Zoology in Jena, and 

 author of a great series of monographs on Radiolarians, 

 Sponges, Jellyfish, etc., may be well called the Darwin of 

 Germany. He has devoted his life to applying the doctrine 

 of descent, and to making it current coin among the people. 

 Owing much of his motive to Darwin, he stood for a time 

 almost alone in Germany as the champion of a heresy. 

 Before the publication of Darwin's Descent of Man, Haeckel 

 was the only naturalist who had recognised the import of 

 sexual selection ; and of his Natural History of Creation 

 Darwin writes : " If this work had appeared before my 

 essay had been written, I should probably never have com- 

 pleted it." His most important expository works are the 

 above-mentioned Naturliche ScMpfungsgeschickte (ist ed. 

 1868; 8th ed. 1889); and his .(4 !^//%ra/og-^«zV (1874, trans- 

 lated as The Evolution of Man). These books are very 

 brilliantly written, though they offend many by their remorse- 

 less consistency, and by their impatience with theological 

 dogma and teleological interpretation. His greatest work, 

 however, is of a less popular character, namely, the Generelle 

 Morphologic (2 vols., Berlin, 1866), which in its reasoned 

 orderliness and clear generalisations ranks beside Spencer's 

 Principles of Biology. 



Huxley, by whose work the credit of British schools of 

 zoology has been for many years enhanced, was one of the first 

 to stand by Darwin, and to wield a sharp intellectual sword 

 in defence and attack. No one has fought for the doctrine 

 of descent in itself and in its consequences with more keen- 

 ness and success than the author of Man's Place in Nature 

 (1863), American Addresses, Lay Sermons, etc., and no one 



