Chemical Agents on the Nervous Si/stem, 39 



and c, and inverse in b and d. After ten minutes of con- 

 tinuous current, all the limbs were aifected with tetanoid 

 spasm on breaking the circuit. After the lapse of a longer 

 time, the current being removed and uninterrupted, the te- 

 tanoid spasm ceased first on breaking the circuit in the limbs 

 a and c, remaining in b and d\ on remaking, a single move- 

 ment was observed in a and c, while b and d became simply 

 flaccid. Such is the difference in the effect, arising from the 

 direct and inverse currents. 



On laying the galvanoscopic frog across from c to d, before 

 and after breaking the circuit, movements were observed in 

 the limb, the nerve being exposed in the former case to the 

 direct, in the latter probably to the inverse current, as de- 

 noted by the arrows. 



I have now to add, that whatever the effect observed on 

 making or breaking the circuit, including the lumbar nerves, 

 may be, a far greater effect is observed on completing the 

 circuit, and connecting the wires of the Voltaic apparatus. 

 This is especially observed in all cases in which the powers 

 are beginning to be exhausted. 



The experiment implies probably not merely the subtrac- 

 tion of the primary Voltaic current, but the institution of a 

 reverse current, and the degree of effect is probably com- 

 mensurate with the difference of the two conditions. To this 

 must be added the effect of the discharge of the electrogenic 

 condition. 



This last is seen in its insulated form, on breaking the 

 Voltaic circuit, and then connecting the wires. It is usually 

 slight, and admits only of being repeated once or twice, each 

 successive connection of the wires producing less effect than 

 the preceding one, consisting in effect, of the discharge of 

 the residual electrogenic condition. 



In the former case, the movements are also more rapid, as 

 well as more energetic, in the latter they are slower, and 

 somewhat more continuous. 



In conclusion I may observe, that I have purposely and 

 carefully avoided all theoretical views, confining myself to 

 the accurate detail of experiments. The condition induced 

 in the nervous system, by a current of Voltaism, I have de- 



