30 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[30 



determinations are therefore more accurate for our purposes than the 

 direct values of length regenerated. 



The first regeneration is slightly below the second not only in case 

 the latter is from new cells but also in case it is from old cells. The 

 difference between first and second regenerations therefore can not be 

 due entirely to the presence in the former of cells which are already 

 undergoing regeneration. 



TABLE 20 



Rana clamitans Series 3628-3675 

 First and second regenerations compared Age factor eliminated 



Eight days 



