STUDIES OF TISSUE GROWTH 



II FUNCTIONAL ACTIVITY, FORM REGULATION, LEVEL OF THE 

 CUT, AND DEGREE- OF INJURY AS FACTORS IN DETER- 

 MINING THE RATE OF REGENERATION. THE REACTION 

 OF REGENERATING TISSUE ON THE OLD BODY 



CHARLES R. STOCKARD 



Pathological Laboratory, Cornell University Medical College, New York City 

 With One Plate and Eight Figures in the Text 



I Introduction 433 



II Material and methods 434 



III The influence of activity and rest on the rate of regeneration 435 



rV Form regulation and arrest of regenerative activity in pieces of the medusa disk 438 



V Relation of the level of the cut to the rate of regeneration 442 



VI Relation of the degree of injury to the rate of regeneration 446 



VII The relation between the rate and amount of regeneration and the physical condition 



of the animal body 462 



Vin Summary and conclusions 466 



IX Literature cited 468 



I INTRODUCTION 



The present contribution is the second of a series of studies 

 aiming towards an analysis of the factors controlHng the rates 

 and limits of tissue growth. The problem is complex, yet the 

 investigator has full access to experimental methods in consider- 

 ing the processes of regenerative growth. Factors regulating 

 regeneration are probably identical with those determining pri- 

 mary or generative growth and if the former could be identified 

 and controlled it might become possible on the one hand to main- 

 tain some forms of growth indefinitely or on the other to suppress 

 certain excessive growths of a pathological nature. 



The Journal of Zoology, vol. vi, no. 3. 



