1869.] Dr. C. B. RadclifFe's Researches in Animal Electricity. 385 



this discharge is the discharge of the opposite electricities of the poles 

 which attends upon the closing of the circuit in any case. Nor is the 

 absence of contraction at the opening of the circuit unintelligible ; for it 

 is easy to see that the loss in the power of contracting which the limb 

 in which the current is direct has experinced by this time, may have ren- 

 dered the limb incapable of responding to the weaker discharge which 

 attends upon the opening of the circuit. 



In the limb in which the current is inverse, as will appear on com- 

 paring the figures 2 & 4, there must be the addition of the artificial charge 

 to the natural charge — a surcharge — a state which may nullify the dis- 

 charge attending upon the closing of the circuit ; and hence the absence 

 of contraction at the closing of the circuit ; for, according to the premises, 

 there will be no contraction if there be no discharge, or, rather, there will 

 be no contraction if there be no sufficient discharge. Nor is a reason 

 wanting for the presence of contraction at the opening of the circuit in 

 this case ; for if the action of the electricity be to preserve and restore the 

 power of contracting in the limb in which the current is inverse, it is easy 

 to suppose that in the case in question this power is so far preserved as 

 to allow the limb to respond to the discharge which attends upon the 

 opening of the circuit. 



Nor need there be any difficulty in dealing with the phenomena be- 

 longing to the other periods of the second stage. The presence of con- 

 traction at the closing as well as at the opening of the circuit, in the case 

 of the limb in which the current is inverse (second stage, first period, in 

 Table), would seem to imply no more than this, that the conditions pre- 

 sent in the first stage have not yet come to an end. The absence of con- 

 traction at the closing as well as at the opening of the circuit in the limb 

 in which the current is direct (second stage, third period, in Table), may 

 merely be due to the electricity having now so far destroyed the power of 

 contracting as to make the limb incapable of responding to the stronger 

 no less than to the weaker of the discharges acting upon it. The 

 differences in question are merely transitional, nothing more. 



A few words will suffice for all that need be said respecting the pheno- 

 mena which remain to be considered (third stage in Table). For if the 

 charges of the poles play the part which has been ascribed to them, it is 

 to be expected that, by reversing the position of the poles, what was done 

 in either limb by either pole may be undone by the other pole, and that 

 at a certain moment after this reversal the two limbs may be restored to 

 that state of similarity in which they will, as at first, contract similarly 

 on closing and opening the circuit, one or both — at the opening as well as 

 at the closing if the battery power be strong, at the closing only if the 

 battery power be feeble. 



It would seem, then, as if the changes of tension, to which attention has 

 been directed, supplied an explanation of the motor phenomena ascribed to 

 the action of the " inverse " and " direct " currents, which, to say the least, 



