PHYSIOLOGY OF REGENERATION 17 



activity of the organism," for what else can this fact signify except 

 that the physiological activities are lessened? The argumenta- 

 tion might justly and with equal pertinency be turned against 

 the opposite proposition, viz., that an increase of the regenera- 

 tive rate after successive injuries is the result of an acceleration 

 of the physiological activities; but nothing could be gained by 

 such an argument, which simply translates a tangible fact into 

 an elusive conjecture, and in neither case leads anywhere. 



The fact which commands our attention is that, while the regen- 

 erative process after the first operation is already declining, a new^ 

 operation will cause a new output of regenerative energy exceed- 

 ing the possible output where there had been no other injury in the 

 meantime. In fact the worms operated on twice at intervals of 

 two wrecks regenerated during the space of four weeks an average 

 of 11.6 segments, whereas after a single operation, but within a 

 similar period of four weeks, only 8.4 segments regenerated. In 



other words, there w^as an average excess of over 3 segments 

 caused by the repeated operation, even though the rate of regen- 

 eration the second time was somewhat decreased. 



From table 8 it will likewise be seen that, while in three weeks 

 the worms regenerated an average of 7.6 segments (5 to 11 seg- 

 ments), the average number of regenerated segments for three 

 weeks following a repeated, mutilation decreased to 6.1 (5 to 9 

 segments) . 



The Journal op Experimental Zoology, Vol. 10, No. 1. 



