390 Dr. C. B. RadclifiVs Researches in Animal Electricity. [Apr. 8, 



In the first stage of the experiment the facts are — suspension of the 

 tetanus caused by the salt during cathelectrotonus and anelectrotonus alike, 

 return of tetanus after anelectrotonus, momentary contraction only after 

 cathelectrotonus ; and these facts are not inexplicable. The tetanus after 

 anelectrotonus, and the momentary contraction only after cathelectrotonus, 

 show, as it would seem, that the power of responding to the action of the 

 salt has been preserved in anelectrotonus, as in the case of the limb in 

 which the current is inverse, and lost in cathelectrotonus, as in the case 

 of the limb in which the current is direct. It is quite intelligible also that 

 the tetanus caused by the salt should be suspended during the continuance 

 of the electrotonic state, if this state be based upon charge, and if this 

 charge have that power of counteracting contraction which would seem to 

 belong to it. 



In the other steps of the experiment the two topics which have to be 

 considered are (1) what happens when anelectrotonus follows cathelec- 

 trotonus, and (2) what happens when cathelectrotonus follows anelectro- 

 tonus. 



In the case in which anelectrotonus follows cathelectrotonus the facts 

 are these : — during anelectrotonus, rest at first, then twichings progres- 

 sively increasing in frequency and force ; and after anelectrotonus, tetanus ; 

 and so it should be. If, indeed, the power of contracting is impaired in 

 cathelectrotonus and preserved in anelectrotonus, it may be supposed, 

 when anelectrotonus is made to follow cathelectrotonus, that the power of 

 contracting has been so far impaired by the previous state of cathelectro- 

 tonus as to oblige the muscles to remain in a state of rest until this power 

 is to a certain degree restored by the state of anelectrotonus ; and that the 

 rest at first, and the twitchings progressively increasing in force and fre- 

 quency afterwards, when anelectrotonus is made to follow cathelectrotonus, 

 may be accounted for in this way. Moreover the tetanus upon the ces- 

 sation of anelectrotonus may be supposed to receive its explanation also, 

 if the action of the anelectrotonus has been to preserve and restore the 

 power of contraction, and if the state of charge upon which that of anelec- 

 trotonus is based, has, in some degree at least, the effect of counteracting 

 contraction. 



In the case of cathelectrotonus after anelectrotonus, also, what happens 

 is intelligible enough when the same principles of interpretation are applied 

 to the facts. The facts themselves are these : — during cathelectrotonus, 

 first tetanus, then rest; after cathelectrotonus, momentary contraction. 

 Now when cathelectrotonus follows upon anelectrotonus, as a comparison 

 of figs. 3 & 4 will show, there must be discharge. And, further, when 

 either electrotonic state is established, there must be that discharge which 

 attends upon the closing of the circuit in any case ; and hence the tetanus 

 which happens when cathelectrotonus is made to follow anelectrotonus ; for 

 in addition to being acted upon by the salt, the muscles (the power of con- 

 tracting is preserved in anelectrotonus) are at this time acted upon by the 



