18 TABLE OF CONTENTS 



CHAPTER XIII 



PAGE 



Transmission of Acquired Characters: Theo- 

 retical Controversies 189 



Importance of the question. — Evidence from 

 daily observation. — Darwin on the transmission of // 

 acquired characters. — Modern controversies. — 

 Definition of acquired characters by Montgomery, 

 Le Dantec, Weismann. — What the Weismannians 

 reject. — An arduous problem. — Spencer versus 

 Weismann; the papillae of the tongue; the sense of 

 touch; the degeneration of the fifth toe; seasonal 

 dimorphism of butterflies, neuter ants and bees. 



CHAPTER XIV 



Transmission of Acquired Characters. Obser- 

 vations and Experiments 210 



Experiments instituted to ascertain the hereditary 

 transmission of acquired characters. — Mutilations 

 and disease. — Brown-Sequard's guinea pigs. — The 

 adaptation of living beings to external conditions. 

 — Variations produced in butterflies by temperature 

 and food: experiments made by Kellogg and Bell, 

 Pictet, Fisher. — Influences producing local modifi- 

 cations: facts instanced by Cunningham, Hyatt, 

 Cattaneo. — Transmission of psychical characters 

 such as a talent for music. How acquired charac- 

 ters may possibly be transmitted. — A chemical 

 theory; the theories of A. Gautier, Le Dantec and 

 Montgomery. — The proper method to follow. 



