Influence of Regenerating Tissue on the Animal Body. 



47 



in diameter while Group II was 69 mm., or 7 mm. larger. After 22 days 

 they were 55.3 mm. and 63 mm., and after 28 days 51 mm. and 59 mm. 

 It will be noted, however, that Group I ceased to decrease rapidly after 

 the first 14 days, when its rapid regeneration also ceased, and from this 

 time on it decreased almost as slowly as Group II, since in the last 6 days 

 of the experiment it lost only 4.3 mm., while Group II lost 4 mm. 



The rate of growth for the arm-buds in table v is practically the 

 same as from the specimens similarly injured in the previous experiment. 



Groups I and II again show that when a specimen regenerates a 

 certain amount of tissue in a given time such a specimen suffers a loss 

 in body size which is greater than the loss from other specimens regenerat- 

 ing a less amount of tissue. Regenerating tissue, therefore, consumes 

 the old body-substance and has an effect which would finally so weaken 

 the body as to cause death should the regeneration continue for a sufficient 

 time. A method which could eliminate the factors that cause growth 

 to cease when an organ has attained a certain size would allow the organ 

 to grow at the expense of the other body parts until death would follow 

 in a manner closely similar to that by which a malignant tumor growth 

 finally kills the body containing it. The absence of certain of the growth- 

 inhibiting substances in the body may be responsible for the indefinite 

 cancer growths, and experiments that in any way lead to a determina- 

 tion of the controlling factors in normal, primary, or secondary growths 

 are of great importance in this regard. 



TABLE IV. Record of disk diameters and regeneration from Cassiopca, when all of 

 the oral-arms and the stomach are removed (in millimeters). 



