CO-ORDINATION. 131 



parts of the swimming-bell seem to contract at the 

 same instant. And this apparently perfect co- 

 ordination amono- the eiii'ht marginal o-ano'lia mav 



O O O O O V 



continue for any length of time. I believe, however, 

 that such apparently complete physiological har- 

 mony is not co-ordination properly so called, i.e. is 

 not due to special nervous connections between the 

 ganglia ; for, if such were the case, perfectly syn- 

 chronous action of this kind ought to be the rule 

 rather than the exception. 



I am therefore inclined to account for these cases 

 of perfectly synchronous action by supposing that 

 all, or most, of the ganglia require exactly the same 

 time for their nutrition ; that they are, further, of 

 exactly equal potency in relation to the resistance 

 (or excitability) of the surrounding contractile 

 tissues ; and that, therefore, the balance of forces 

 being exactly equal in the case of all, or most, of the 

 ganglia, their rhythm, though perfectly identical, is 

 really independent. I confess, however, that I am 

 by no means certain regarding the accuracy of this 

 conclusion, as it is founded on negative rather than 

 on positive considerations : that is to say, I arrive 

 at this conclusion regarding the cases in which such 

 apparent co-ordination is observable only because 

 in other cases such apparent co-ordination is not 

 observable ; and also, I may add, because my 

 experiments in section have not revealed any 

 evidence of nervous connections capable of con- 

 ducting a stimulus-wave with greater rapidity than 

 a contraction-wave. I therefore consider this con- 

 clusion an uncertain one, and its uncertainty is, 



