350 HEREDITY AND ENVIRONMENT 



and this modified character appears in the 

 next generation. If this is an after effect or 

 "induction" it should disappear in the follow- 

 ing generations. 



Kammerer found that black- and yellow- 

 spotted salamanders, reared on yellow soil 

 gradually lose their black color becoming more 

 yellow, and their young continue to grow more 

 yellow until, finally almost all black may dis- 

 appear. The offspring of such salamanders 

 are more yellow than normal ; but this also may 

 be an after effect or "induction" which would 

 soon disappear under usual conditions. 



Probably such cases are not instances of true 

 inheritance ; they do not signify a change in the 

 hereditary constitution but an influence on the 

 germ cells of a nutritive or chemical sort com- 

 parable with what takes place when fat stains 

 are fed to animals; the eggs of such animals 

 are stained and the young which develop from 

 such eggs are also stained, though the germi- 

 nal constitution remains unchanged. The 

 very fact that the changed condition is reversi- 

 ble and that it disappears within a short time 

 is evidence that it is not really inherited. 



