RATE OF REGENERATION IN CASSIOPEA 29 



The latter experiments have not been carried far enough to give 

 a definite answer to the question of whether or not there is a 

 gradual decline in the difference in the rate of metabohsm cor- 

 responding to that shown in regeneration. 



This result clearly supports the general contention of Child 

 that the influence of the nervous system on regeneration is in- 

 direct, rather than dhect, but does not confirm his statement 

 that there is a direct relationship between the rapidity of regen- 

 eration and the '' characteristic motor activity of the parts con- 

 cerned." It is shown, that, on the contrary, motor activity may 

 be greatly increased without altering to a proportional extent 

 either the rate of regeneration or general metabolism. 



The rate of regeneration appears to be simply one expression 

 of the general metabolic activity of an organism and consequently 

 to be subject to the control of the nerve centers in the same 

 manner as the many other functional activities for some of which, 

 at least, a direct nervous control can not be denied. 



SUMMARY 



1. The experiments with entire disks, where the rates of re- 

 generation of specimens on which the sense organs remained are 

 compared with those of specimens from which all sense organs 

 are removed, are inconclusive because of wide differences in 

 physiological activity between different individuals. 



2. \ATien the insulated halves of a disk, on one of which the 

 sense organs remain, while all of them have been removed from 

 the other half, are compared it is found that the half disk with 

 sense organs always regenerates most rapidly. This is especially 

 noticeable in the early stages of regeneration. The difference in 

 rate falls gradually throughout the course of an experiment 

 (p. 7) (table land fig. 4). 



3. When disks prepared as in the experiments mentioned in 

 the previous paragraph are allowed to regenerate in sea water 

 plus 15 parts 0.6 m MgS04, the regeneration is at first more rapid 

 from the half on which the sense organs remain. Within a few 

 hours the sense organs come under the influence of the anesthetic 



