OF ENVIRONMENT 123 



alteration gradually disappeared when the induc- 

 ing conditions were removed, except in a few 

 instances in which it could not he demonstrated 

 that the germ-plasm had not been directly 

 affected. 



Butterflies, moths, fishes, crustaceans, birds, 

 guinea pigs, rabbits, trees, fungi, cereals, and 

 bulbous plants have all been drawn into the ex- 

 perimental field with a remarkable unanimity of 

 negation in so far as the somatogenic induction 

 of characters was solely concerned, which might 

 be fully transmissible to successive generations 

 not under the influence of the exciting factors. 

 Temperature, light, food, and composition of the 

 medium or substratum all have been tested in 

 their various effects. Only when the germ-plasm 

 has been acted upon simultaneously with the 

 soma has any well-defined reappearance of in- 

 duced characters in succeeding generations been 

 noted, and of the earlier results those of Stand- 

 fuss and Fischer seem most notable, since in ex- 

 periments with Vanessa and Arctia the applica- 

 tion of special temperatures or the modification 

 of nutritive conditions induced the formation of 

 aberrant characters in some of the offspring. The 

 new quahties were displayed in varying degree, 

 and maintained their distinctive appearance in 

 the products of hybridization with the parental 

 strain. There seems to be some doubt among 

 zoologists acquainted with these forms as to the 

 significance of these results. It is not clear as 



