536 Experimental Studies on the Origin of the Lens in Ampliibia 



and that through interaction of these new stuffs are formed which be- 

 come localized in different portions of the egg and during cleavage into 

 certain groups of cells. It is evident that this localization into groups 

 of cells does not prevent farther interaction and formation of more and 

 more specific stuffs, which are the determining components of the 

 various organs and tissues. Thus the specific stuffs which determine the 

 development of the lens are not formed until a comparatively late period 

 in development. 



