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 they 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. 



MacDougal, 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, apparently bred true to the 

 newly induced character. This is an instance of what 

 has been termed "parallel induction," where somato- 

 plasm and germplasm are affected together by an ex- 

 ternal factor, as opposed to "somatic; induction" or 

 Weismannian acquired characters, in which the germ- 

 plasm is secondarily influenced through, or by the 

 agency of, the somatoplasm. Sitkowski fed the cater- 

 pillars of the moth Tineola biselliella 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 apparent case of parallel induction, 

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

 of animals who got their red color while they were 

 eggs within the mother's body. 



