84 GENETICS 



10. WEISMANN'S REASONS FOR DOUBTING THE INHER- 



ITANCE OF ACQUIRED CHARACTERS 



Weismann's reasons for questioning the popularly 

 accepted view that acquired characters are inherited 

 may be briefly stated as follows : 



First, there is no known mechanism whereby 

 somatic characters may be transferred to the germ- 

 cells. 



Second, the evidence that such a transfer actually 

 does occur is inconclusive and unsatisfactory. 



Third, the theory of the continuity of the germ- 

 plasm is sufficient to account for the facts of heredity 

 without assuming the inheritance of acquired somatic 

 characters. 



Let us examine these three statements a little more 

 closely. 



11. No KNOWN MECHANISM FOR IMPRESSING THE 



GERMPLASM WITH SOMATIC CHA-RACTE,R^S 



The somatoplasm is something that has traveled 

 out from the original fundamental germplasm along 

 the paths of differentiation and elaboration. The 

 more complex the body cells become, that is, the 

 more .successive modifications they undergo, the more 

 difficult it is for these somatic cells to return to their 

 original primitive estate. 



In many lower forms of life where cell elaboration 

 is not so great, a part lost by amputation is often 

 regenerated, but this process is not possible in higher 



