250 ERNST MAECKEL AND CARL GEGENBAUR 



the " theory of the repetition of parts," of which so much 

 use was made by the German transcendentalists, such as 

 Goethe, 1 Oken, Meckel and K. G. Carus, as well as by 

 Duges. 



The third, and naturally the most important, ingredient 

 in the General Morphology was the*"doctrine of evolution, 

 in the form given to it by Darwin. We have here no 

 concern with Haeckel's evolutionary philosophy, with the 

 way in which he combined his evolutionism and his 

 materialism to form a queer Monism of his own. \Ye 

 are interested only in the way he applied evolution 

 to morphology, what modifications he introduced into the 

 principles of the science, and in general in what way 

 he interpreted the facts and theories of morphology in 

 the light of the new knowledge. 



We find that he repeats very much what Darwin said, 

 giving, of course, more detail to the exposition, and elaborat- 

 ing, particularly in his recapitulation theory or " biogenetic 

 law," certain doctrines not explicitly stated by Darwin. 



Like Darwin he held that the natural system is in reality 

 genealogical. "There exists," he writes, "one single con- 

 nected natural system of organisms, and this single natural 

 system is the expression of real relations which actually 

 exist between all organisms, alike those now in being 

 on the earth and those that have existed there in some past 

 time. The real relations which unite all living and extinct 

 organisms in one or other of the principal groups of the 

 natural system, are genealogical : their relationship in form 

 is blood-relationship; the natural system is accordingly the 

 genealogical tree of organisms, or their genealogema. . . . All 

 organisms are in the last resort descendants of autogenous 

 Monera, evolved as a consequence of the divergence of 

 characters through natural selection. The different 

 subordinate groups of the natural system, the categories 

 of the class, order, family, genus, etc., are larger or smaller 

 branches of the genealogical tree, and the degree of their 

 divergence indicates the degree of genealogical affinity of the 



1 Ilacckel had an intense admiration for. Goethe's morphological 

 work. It is a curious coincidence that the work of Goethe, Oken 

 and Hacckel was closely associated with the town of Jena. 



