90 WHAT EVOLUTION IS 



experiments could be devised that 

 would of necessity last over a number 

 of generations, results of a very dif- 

 ferent kind might be obtained. 



To try out this aspect of the prob- 

 lem numerous investigations have 

 been made or are still in progress. 

 Few workers have done more in this 

 direction than the Viennese experi- 

 mentalist, Kammerer. Of his num- 

 erous studies one may be chosen as 

 an example. The European spotted 

 salamander deposits either numerous 

 eggs or young that have been hatched 

 in the mother's body in ponds and 

 pools in damp woods. All the young, 

 irrespective of their condition of 

 birth, are provided with gills and 

 live for several months in the water 

 after which they lose their gills and 

 become inhabitants of the land. The 

 European black salamander gives 

 birth only to active young, usually 



