ACQUIRED CHARACTERS 71 



aniline dye (Sudan red III), obtaining therefrom, in- 

 stead of normal whitish ones, moths that laid col- 

 ored eggs, and these in turn hatched into caterpillars 

 still tinged with the color of the red dye. Riddle, with 

 guinea-pigs, and Gage, with poultry, obtained quite 

 similar results. This case of apparent parallel induc- 

 tion, however, is not a matter of inheritance at all, 

 since the germinal substance itself was not involved, 

 but of animals who got their red color directly from 

 external sources while they were eggs within the moth- 

 er's body. 



10. WEISMANN'S REASONS FOE 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. 



A. NO KNOWN MECHANISM FOR IMPRESSING THE 

 GERMPLASM WITH SOMATIC ACQUISITIONS 



Each germ-cell remains an independent unit and 

 does not participate in the activities of the body but 



