INTRODUCTION 



The question of the inheritance of acquired characters 

 is one which, by its generality, by its importance for the 

 theory of the origin of species, and by its close connec- 

 tion with still more difficult questions concerning the 

 essential nature of life lying in the border land between 

 physical chemistry and biology, passes beyond the con- 

 fines of pure biology, and enters the wider field of posi- 

 tive philosophy in the sense of August Comte, that is of 

 scientific philosophy, which concerns itself with the most 

 general results of the various sciences and with their 

 fundamental interrelations. Is it any wonder then that 

 this much discussed but unsolved question excites the 

 keenest interest in philosophers and even induces some of 

 them though they are not specialists, to attempt to study 

 it thoroughly utilizing the abundant and valuable mate- 

 rial which biologists and naturalists can now supply? 



It is so with the author of the present study. 



Formerly when he had not yet formed any fixed and 

 definite opinion upon this subject, he had been inclined in 

 a few philosophical and sociological studies to prefer 

 Weismann's theory of the non-inheritance of acquired 

 characters to the contrary theory of Lamarck. The rea- 

 son for this inclination even though no logically tenable 

 opinion had been formed, lay in the demonstrated inabil- 

 ity of any of the biological theories which had then been 



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