TRANSMISSION OF CHARACTER 203 



searching and inclusive controversy. 7 Spencer started 

 it by criticising Weismann's statement that natural 

 selection was the all-sufficient factor in the evolution 

 of species. We reviewed elsewhere his most impor- 

 tant arguments. We will only mention here the coun- 

 terpart of the argumentation, that is, the discussion 

 touching the heredity of acquired characters, a factor 

 which Spencer, while he does not deny the effects of 

 natural selection, believes to be as important as selec- 

 tion. "Natural selection or survival of the fittest is 

 almost exclusively operative throughout the vegetal 

 world and throughout the lower animal world, char- 

 acterised by relative passivity. But with the ascent 

 to higher types of animals, its effects are in increasing 

 degrees involved with those produced by inheritance 

 of acquired characters; until, in animals of complex 

 structures, inheritance of acquired characters becomes 

 an important, if not the chief cause of evolution." 



The heredity of acquired characters is always a fac- 

 tor either alone or in combination with natural selec- 



i H. Spencer. Inadequacy of Natural Selection (Contemporary Re- 

 view, Feb., March and May, 1893) ; A Rejoinder to Prof. Weismann 

 (Ibid., Dec, 1893); Weismannism Once More (Ibid., Oct., 1894). Weis- 

 maxx: The All-sufficiency of Natural Selection (Ibid., Sept., 1893); The 

 Effect of External Influence upon Development (The Ro7iianes Lecture, 

 1894) ; Neue Gedanken zur Vererbungsfrage. Eine Antwort an Herbert 

 Spencer (1895). 



s Principles of Biology. Appendix B. Inadequacy of Natural Selec- 

 tion, p. 632. 



