92 WHAT EVOLUTION IS 



an advanced stage of groWth, and 

 these young remained in the water 

 only a few days instead of several 

 months. Thus the reproductive hab- 

 its of the spotted salamander, by a 

 change in the environment, were 

 modified in the direction of the black 

 salamander, and this modification 

 persisted more or less in their de- 

 scendants, even after these descend- 

 ants had been allowed to return to 

 the original environment. 



Several lines of experimentation 

 such as the one described in the pre- 

 ceding paragraph have been carried 

 out by Kammerer within the last few 

 years and point to the inheritance of 

 acquired characters. How sound the 

 experimental evidence is in all such 

 cases remains to be seen. Is it not 

 possible that the peculiarities that 

 Kammerer believed he originated in 

 the spotted salamander, to take this 



