Factors in Regeneration 



329 



The above tables give the number regenerated at the basal ends 

 of pieces 3, 6 and 9 days after amputation. The oral (and lateral 

 polyps also) had not been cut off but disappeared within two days. 

 Regeneration, therefore, at oral and lateral ends could not take 

 place till one or two days after the basal polyps appeared. 



Regeneration in one direction^ viz: from the basal end of B 

 piece does not inhibit regeneration in the opposite direction at c; 

 rapid growth and differentiation take place synchronously in opposite 



\ 



/ 



A < 



\ 



\ 



_ _ _a or a 



I end 



/ 



/ 



/ 



oral enci _ 



B 



/ 



_ _ _ [r Ij-aSQL end 



/ 



_ c 



.1 



en 



d 



/ 



\ 



\ 



C 



B 



OrQi 



Fig. I 



directions. This would lend weight to the view that regeneration 

 is not dependent on internal changes of the entire stem or even 

 parts of the stem but is rather due to reactions at the cut end only.* 

 An examination of Tables 14 and I5will make itclearat aglance 

 that gravity is a considerable factor in determining the increase or 

 decrease of the number of hydranths at the upper ends (toward 

 the zenith), regardless whether such ends be oral or basal. Erect 



* Except for minute pieces, see also Experiment 25 on this point. 



