28 LEWIS R. CARY 



i.e., the nearer to the center of the disk — the faster would be the 

 following regeneration. 



In my experiments the amount of tissue removed from the 

 margin of each half of any disk was the same. The differences 

 in result observed were, therefore, due to the difference in kind 

 not in quantity of tissue removed. As recorded in a previous 

 statement (p. 7) the difference in rate of regeneration is in Cassi- 

 opea greatest in the early stages and gradually declines through- 

 out its course, at least through the periods followed in these experi- 

 ments. Goldfarb's observations appear also to show a similar 

 course of events in earthworms, starfish and amphibians. 



This result, on the other hand, is opposed to the conclusion of 

 Child ('10) that "as most experiments not only on the Turbel- 

 laria, but on other forms, indicate it is probable that the early 

 stages of the formation of new tissue are largely or wholly inde- 

 pendent of the nervous system " The later part 



of the same statement, ''but it is difficult to understand how the 

 nervous system of an adult animal could fail to affect the amount 

 and rapidity of growth in an regenerating part composed largely 

 of muscles and sense organs. Absence of such an effect would 

 be in direct opposition to the well established fact of the func- 

 tional influence of the nervous system on various parts of the 

 organism," is in perfect accord with my results. 



Morgulis' ('12) conclusion from his experiments on Brittle 

 Stars that the presence at the cut surface of the radial nerve, 

 either with or without its being in continuity with the remainder 

 of the nervous system, is a ''conditio sine qua non" for normal 

 regeneration and that the presence — ^purely as a mechanical 

 matter — not the functional activity of the nerve is the important 

 factor in regeneration is in direct opposition to my results. 



A study of the figures illustrating his paper shows, neverthe- 

 less, that the arms in which the nervous connection is undis- 

 turbed (control) regenerates most rapidly. 



As to the nature of this influence it is evident from the study 

 of the rate of general metabolism of half disks with and without 

 sense organs that it is closely associated with, if, indeed, not iden- 

 tical with, the control of the general metabolism of the animal. 



