INHERITANCE OF ACQUIRED CHARACTERS 83 



germplasm, regardless of any simultaneous modifica- 

 tion of the somatoplasm, must be excluded as irrele- 

 vant to a discussion of the heritability of acquired 

 characters in the Weismannian sense, since thev are 

 not somatic modifications at all. 



Many instances of direct influence of external 

 stimuli upon germplasm are known in biological 

 literature, and these have led to some of the misunder- 

 standings concerning the "interminable question" of 

 the inheritance of acquired characters. 



MacDougall, for example, was able by injecting 

 certain salts into the carpels of plants to stimulate 

 the germplasm of the forming seeds so directly that 

 a progeny of modified character was produced which, 

 in succeeding generations, bred true to the newly in- 

 duced character. 



Sitkowski, also, fed the caterpillars of the moth 

 Tineola bisellieUa with, an aniline dye (Sudan red III), 

 obtaining therefrom, instead of the normal whitish 

 ones, moths that laid colored 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 is 

 an instance of what has been termed *' parallel induc- 

 tion " where somatoplasm and germplasm are affected 

 together by an external factor, as opposed to " somatic 

 induction " or Weismannian acquired characters in 

 which the germplasm is secondarily influenced through, 

 or by the agency of, the somatoplasm. 



