KOLLIKEirS CRITICISM OF DARWIN 243 



mulgated in a critical note on Darwinism a sketch of his 

 theory of " heterogeneous generation." l 



Kolliker's attitude is typical of that taken up by many 

 of the morphologists of the day. 2 He accepts evolution 

 completely, but rejects Darwinism because it recognises 

 no Eiitivickelungsgesetz, or principle of evolution. For the 

 Darwinian theory of evolution through the selection of small 

 fortuitous variations he would substitute the theory of 

 evolution through sudden, large variations, brought about 

 by 'the influence of a general law of evolution. This is 

 his theory of heterogeneous generation. " The fundamental 

 idea of this hypothesis is that under the influence of a general 

 law of evolution creatures produce from their germs others 

 which differ from them" (p. 181). It is to be noticed 

 that Kolliker laid more stress upon the Entwickelnngsgesetz 

 than upon the saltatory nature of variation, for he says a 

 few pages further on " the notion at the base of my theory 

 is that a great evolutionary plan underlies the development 

 of the whole organised world, and urges on the simpler forms 

 towards ever higher stages of complexity" (p. 184). 

 Saltatory evolution was not the essential point of the 

 theory : " Another difference between the Darwinian 

 hypothesis and mine is that I postulate many saltatory 

 changes, but I will not and indeed cannot lay the chief 

 stress upon this point, for I have not intended to maintain 

 that the general law of evolution which I hold to be the 

 cause of the creation of organisms, and which alone mani- 

 fests itself in the activity of generation, cannot also so 

 act that from one form others quite gradually arise" (p. 185). 

 He put forward the hypothesis of saltatory variation because 

 it seemed to him to lighten many of the difficulties of 

 Darwinism the lack of transition forms, the enormous time 

 required for evolution, and so on. It should be noted that 

 Kolliker regarded his principle of evolution as mechanical. 



1 " Ueber die Darwinische Schopfungstheorie," Zeitx. f. wtss. Zool. t 

 xiv., pp. 74-86, 1864. Elaborated in Anat. u. syst. Beschreibung d. 

 Alcyonarien, 1872. 



2 Cf. for instance Nageli's theory of a perfecting principle, first 

 developed in his Entstchung u. Begrijf der natiirhistorischer Ari, 

 MUnchen, 1865. 



