CHAPTER XIII 



Transmission of Acquired Characters: 

 Theoretical Controversies 



Importance of the question." — Evidence from daily observation. — 

 Darwin on the transmission of acquired characters. — Mod- 

 ern controversies. — Definition of acquired characters by 

 Montgomery, Le Dantec, Weismann. — What the Weismann- 

 ians reject. — An arduous problem. — Spencer versus Weis- 

 mann; the papillae of the tongue; the sense of touch; the 

 degeneration of the fifth toe; seasonal dimorphism of butter- 

 flies; neuter ants and bees. 



THE most important fact in biology, adaptation, 

 is accounted for at present either by natural 

 selection of innate variations, or by the inheritance of 

 acquired characters. Between the two theories there 

 is an impassable chasm, and each of them places an 

 absolutely different construction upon a multitude of 

 other questions, such as the process of ontogenesis, 

 regeneration, heredity, etc. We may add that upon 

 the solution of the problem, depends the solution not 

 merely of many biological questions but of many 

 moral and social questions as well. 



The inheritance of acquired characters has become 



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