49] 



RATE OF REGENERATION— ZELENY 



TABLE 32 



Amblystoma punctatum Series 3967-399S Age factor eliminated 



Comparison of lengtlis of first, second and third regenerations 



Comparison of individual cases 



Comparisons 



3rd regen. > 1st 

 3rd regen. = 1st 

 3rd regen. < 1st 



2nd regen. > 1st 

 2nd regen. = 1st 

 2nd regen. < 1st 



3rd regen. > 2nd 

 3rd regen. = 2nd 

 3rd regen. < 2nd 



Two 

 days 



Four 

 days 



Ten 

 days 



Fourteen 

 days 



Totals 



20 

 1 



4 



ExPERiJiENT IV Amblystoma punctatum Series 3962-3999 



The series used for Experiment III furnishes another set of data 

 for the effect of successive removal. When the third operation was made 

 the removed regenerated tails of the first thirty individuals represented 

 an eleven-day second regeneration and those of the second thirty-indi- 

 viduals an eleven-day first regeueration. A direct comparison is thus 

 possible between the first and the second regenerations. It is not possi- 

 ble to make a cut exactly at the border line between old and new tissue 

 and therefore the measurement of the removed regenerating tail is not 

 as accurate a determination as is the direct measurement of a regener- 

 ating unremoved tail. 



The data are shown in Table 33. Twenty-five individuals are avail- 

 able for each regeneration. The average of the first regenerations is 

 4.55 =0.11 and of the second regenerations 4.50 -0.10. The first regen- 

 eration is ahead of the second in ten cases, the second is ahead of the 

 first in twelve cases and three cases are equal. The first comparison 

 shows a slight difference in favor of the first regeneration but this is 

 so much less than the probable error that it can not be considered as 

 significant. The second comparison shows a slight advantage in favor 

 of the second regeneration. On the whole the data indicate essential 

 equality between the first and the second regenerations at eleven days. 



