Summary of This Chapter 223 



chapter, we are able to affirm that although no fact or 

 argument is capable by itself alone of affording an ir- 

 refutable and unconditional proof either direct or indirect, 

 of the inheritance of acquired characters, nevertheless the 

 sum total of the facts and the arguments which are fa- 

 vorable to it is so weighty that one is not only justified in 

 believing but is even compelled to believe that the 

 Lamarckian principle is in all probability correct. 



But the difficulties of explaining the mechanism of 

 inheritance are so great, that many investigators may 

 have thought them to be insurmountable. It is conceiv- 

 able that many others, like Roux, have been led to dis- 

 pute its existence, just in order to free themselves in that 

 way from a veritable nightmare. But this position is no 

 longer possible. 



The objective examination of the question leads to 

 the conviction that the inheritance of acquired characters 

 is to be considered as in all probability a reality, there- 

 fore we are in duty bound to seek an explanation of this 

 phenomenon by some hypothesis, even if it be only a 

 provisional one. 



So in the following chapter we propose to examine 

 comparatively a few of the most recent and most im- 

 portant hypotheses which have been devised for the 

 explanation of inheritance. After that in the penultimate 

 chapter we shall set forth more thoroughly the explana- 

 tion of the Lamarckian principle which the centro- 

 epigenetic hypothesis can give. 



Further evidence that somatic changes induced in animals by 

 environmental influences may be repeated in their descendants as 

 a result of germinal influences is furnished by Sumner and by 

 Kammerer. See Archiv fiir Entwicklungs Mechanik der Organ- 

 ismen, Leipzig, June and September, 1910. (Translator.) 



