C0 2 IN RELATION TO REGENERATION IN PLANARIA. 



make them more nearly comparable in condition with the ^.-pieces 

 and the headless regenerated animals. 



Experiment I of Table IV. includes one lot of each of the three 

 groups and it is seen that the "old" parts of the regenerated 



TABLE IV. 



MISCELLANEOUS DATA. 



Regenerated animals from which anterior and posterior new tissue has been 

 removed, compared with A-pieces and with large headless animals: whole re- 

 generated animals compared with /1-pieces and with growing worms of same size 

 from stock. Fed or unfed. Determinations of pH at 18 C.; pH at beginning 

 of experiment 7.8. 



animals show a higher rate of change than the ^4-pieces, while 

 the headless large animals show the lowest rate of all. 



In Experiment 2 the "old" parts of regenerated animals are 

 compared with A -pieces, both lots being fed three times before 

 sectioning. The result is the same as in experiment I, the rate 

 being distinctly higher in the parts of regenerated animals than 

 in the A -pieces. 



In experiment 3 the "old" parts of regenerated animals are 

 compared with large old animals from which the heads have not 

 been removed, both lots being fed three times after a star- 

 vation period of about two weeks. The result is the same as in 

 Experiment I, the parts of regenerated animals showing the 

 higher rate. 



Experiment 4 is a comparison of A -pieces with entire regen 

 crated animals, i.e., including the new heads and posterior 



