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Dr. C. B. Radcliffe on Animal Electricity. [June 16, 



entirely when nerve and muscle pass from trie state of rest into that of 

 action. The " secondary contraction " set up in a muscle by simply 

 laying its nerve upon another muscle or nerve in which a state of action is 

 present, points to a disturbance outside the acting nerve and muscle such 

 as might be caused by a discharge of electricity, and suggests the idea 

 that the sudden disappearance of nerve-current and muscle-current in action 

 may be owing to such discharge ; and this view is not a little borne out by 

 certain close anatomical and physiological analogies which are found to 

 exist between the muscular apparatus and the electric organs of the Tor- 

 pedo. In short, the evidence seems to show that a discharge analogous to 

 that of the Torpedo is developed, as Matteucci supposed, when nerve and 

 muscle pass from the state of rest into that of action, and that the dis- 

 charge of the Torpedo itself may be nothing more than the unmasked 

 manifestation of a discharge which occurs in a masked form in every case 

 of nervous and muscular action. 



3. The workings of voltaic electricity, and of electricity generally s upon 

 nerve and muscle. 



Argument. — The behaviour of muscle under the action of the so-called 

 "inverse" and "direct" currents is taken as the text in the present inquiry. 



Contraction in this case plainly belongs, not to the time when the circuit 

 remains closed, but to the moments ^of closing and opening the circuit, 

 when the nerves and muscles are acted upon by instantaneous currents, 

 called extra- currents, which currents are in very deed discharges. These 

 extra-currents agree with ordinary induced currents in their discharge-like 

 character ; but they disagree in their direction, the extra-current at the 

 closing of the circuit taking the same course as the constant current, the 

 extra-current at the opening having the opposite course ; and this point of 

 difference is not to be lost sight of. At first both extra-currents cause 

 contraction ; afterwards, when the muscle and nerve have lost some of their 

 susceptibility to impressions, only that extra-current causes contraction 

 which happens to pass in the same direction as that in which motor im- 

 pulses are transmitted along the motor nerves to the muscles. With this 

 clue, indeed, it is not difficult to trace to its cause every variation in the 

 order of contraction'which characterizes the case in question. 



Nor is it altogether unintelligible that the behaviour of the muscles as to 

 the continuance of these contractions should, under ordinary circumstances, 

 differ in the case where the current is inverse, and in the case where the 

 current is direct. This difference is noticed when the voltaic circuit is in- 

 sulated, but not when an earth- wire is put to either of the poles. With the 

 voltaic circuit insulated, the contractions continue for 60' or longer in the 

 case where the current is inverse, and for no longer than 15' or 20' in the 

 case where the current is direct : with the earth-wire at the negative pole 

 the contractions continue for CO' or longer in the case where the current 



is inverse, and in that in which the current is direct also ; with the earth- 



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