PARALLEL INDUCTION 67 



ance of acquired character, but that the normal gill-breathing 

 form represents a case of arrested development, i.e. of "neotenia." 

 To prove this it is necessary to show that the salamander 

 is the degenerate representative of some form no longer 

 amphibian, which, after having been accustomed to a purely 

 terrestrial existence, has taken to laying its eggs in the water, 

 and that the long gill -breathing tadpole stage is a reversion. 

 Is there the least evidence that this is so ? He argues that 

 change from gill -breathing to lung-breathing is not an acquired 

 character, but a purely germinal character that may be 

 either blocked or released by changing conditions of environ- 

 ment. 1 Surely this is contrary to all we know or imagine 

 regarding the Amphibia. We have always been taught that 

 breathing by lungs represents evolutionary advance fitting the 

 vertebrate for terrestrial existence, and not a retrogression. 

 The complete suppression of the gill-breathing stage cannot be 

 regarded as other than something acquired, although, as this 

 is of the nature of a cutting-out of a developmental stage, while 

 on the one hand it may be regarded as progressive acquirement, 

 on the other it does not strictly come under the heading of the 

 positive acquisitions. 



Also belonging to this border-line group of inheritance of 

 defects due to " parallel induction " are to be cited the cases of 

 increased susceptibility to specific toxines, to which I have already 

 referred the observations of Lustig, Watson, and Carriere with 

 reference to abrin and tuberculin. To these may be added 

 the interesting observation of Schenck 2 and others that the off- 

 spring of hypersensitized fathers and normal mothers are them- 

 selves hypersensitized and exhibit anaphylactic phenomena, for, 

 as I have pointed out, anaphylaxis is a stage in the development 

 of immunity ; and, regarding immunity as a digestive process, 

 as the acquirement of an added power of dissociation of specific 

 toxines and conversion of the same into food-stuffs, the demon- 

 stration is in itself a proof that we may confidently expect by 

 fuller studies along these lines to establish firmly, what several 

 observers have already reported, namely the inheritance of 



1 Walter quotes in support Marie von Chauvin's demonstration that the 

 gill -breathing salamander, Axolotl, can, by habituating it to progressive reduc- 

 tion of the water in its aquarium, be converted into Amblystoma. 



2 Miinchener med. Wochenschrift, 1910, 2514. 



