68 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[68 



Therefore the data after this time are values for the completeness of 

 regeneration rather than for the rate. 



Between twelve and a half and eighteen days after the operation 

 there is no further regeneration in the tails with the four shortest re- 

 movals. Two of them even exhibit a decrease in size. The two longest 

 removals show only a slight increase. At eighteen days the regenerated 

 lengths are respectively 1.0, 1.2, 1.5, 2.6, 4.8 and 7.0 mm. as given in 

 Table 38. The same data are represented in graphic form in Figure 14. 

 Dividing by the removed lengths the fractions obtained are 

 1.0 1.2 1.5 2.6 4.8 7.0 



» • . 1 » and 



1.5 2.8 4.9 8.4 13.1 18.1 



giving specific lengths of 0.67, 0.43, 0.31, 0.31, 0.37 and 0.39. The graph is 

 shown in Figure 15. 



bo 

 c 



7.0 



6.0 



■g 5.0 



4.0 



3.0 



2.0 



1.0 



Figure 14 



1.5 2.8 4.9 8.4 13.1 



— >■ Lengths removed in mm. 

 Rana clamitans Second regenerations Eighteen days 



18.1 



At eighteen days there is very little regeneration at any of the 

 levels and at some of them, especially the shorter removals, a consider- 

 able absorption of regenerated material. Regeneration may therefore 

 be considered as completed at this time. However the measurements for 

 56 days are given in order to show the changes. The regenerated 

 lengths at that time are 0.9, 0.7, 1.6, 2.5, 5.2 and 7.1 mm. These data 



