500 C. M. Child. 



the pieces of Series 71 show sHghtly more regeneration than the 

 others, though the difference is not great. 



Thirty-two days after section the pieces of Series 69 had 

 attained the condition of Fig. 34 and those of Series 71 the con- 

 dition of Fig. 35, the amount being somewhat greater in the 

 latter series. After this time no marked alteration in propor- 

 tions occurred. 



The results obtained from these pieces are not very striking but 

 according to the hypothesis we cannot expect anything more than 

 slight differences in such pieces. Such differences would scarcely 

 attract attention of themselves but when we consider them in 

 connection with the experiments described in the preceding sec- 

 tion their significance is apparent. That they are real is well 

 shown by the fact that in certain series which were used for other 

 purposes but which happened to be of such a kind that they could 

 be used in this connection my notes show a difference in the 



w 



33 ^-^ 



amount of regeneration similar to that just described, though 

 when the experiments were made the significance of such a differ- 

 ence had not occurred to me and the difference did not attract my 

 attention until examination of my notes and drawings was made 

 several months later. 



These results, like those described in previous sections, show a 

 close correlation between the regeneration and the motor activity 

 of the pieces, and I believe that in both cases the conditions con- 

 nected with the functional activity of the parts are the factors 

 which determine the differences in regeneration. 



A comparison of Fig. 35 with Figs. 17 and 18 (Series 79) shows 

 that the amount of regeneration in that piece is greater than 

 in these, although the level from which regeneration occurred is 

 somewhat farther posterior (compare Figs. 12 and 28). If the 

 conclusions reached above are correct less rather than more 

 regeneration should be expected in Series 71 than in Series 79. 

 I believe, however, that a difference in temperature is chiefly 



