Compensatory Regulation. C 



the body, i. e., with the factors controUing the asymmetry of the 

 opercula, but rather with the influence of the presence or absence 

 of the posterior regions of the body upon the process as a whole. 



V. The -(ijth section (p. 8i) gives an account of experiments 

 on the regeneration of the chelae of the Decapod Crustaceans, 

 Gelasimus and Alpheus, with reference, first, to the problem of 

 control of the asymmetry of the chelae in the male Gelasimus and 

 in the male and female Alpheus; second, with reference to the 

 general problem of the influence of parts away from an injured 

 surface upon the character of the regeneration at that surface; and, 

 third, with reference to the influence of the character of the opera- 

 tion upon the moult period. 



Finally, all the data are brought together in a general discussion 

 of the facts of compensatory regulation and their relation to the 

 point of view which considers the organism as a system of mutually 

 interacting parts (p. 96). 



Data. 



i. the leaflets of the compound leaf. 



The simplest instance of the application of the method employed 

 in the present paper is furnished by the experiments on the com- 

 pound leaf of the palmate type, as described in my paper on "The 

 Dimensional Relations of the Members of Compound Leaves." It 

 will not be necessary to go into the details of that paper but a 

 sample result may be of value, because the case there described 

 is a pure instance of change in the uninjured organs without 

 regeneration of the injured one. The main point of the experi- 

 ments may be briefly illustrated by the following quotation from 

 the introduction as given there: 



The individual members of the compound leaf as well as of other parts of the 

 plant respond to stimuli in a definite way. Each member is, however, limited in 

 its reaction by its mechanical and organic relations to the other parts of the leaf. 

 This limit -ition is mutual and as a result of it we get an equilibrium of forces which 

 results in a configuration more or less definite for each species. As a further conse- 

 quence each member must respond not as a unit but as part of a system. If now 

 we have a system of this kind with a definite configuration due to the mutual inter- 

 action of its members and we remove one of the component parts, we must get a 

 disturbance of the equilibrium leading to changes in the relations of the remaining 



