358 



Now, on comparing this last fact with the two previous facts, we 

 may have, as it seems to the author, some insight into the mode in 

 which the galvanic current acts upon nerve in the period of alternate 

 contraction. On the one hand, it is seen that tetanus is prevented or 

 arrested by the inverse current ; that is to say, tetanus is prevented 

 or arrested when (as the first and second facts show) the galvanic 

 current coincides in direction with, and imparts power to, the nerve- 

 current. On the other hand, it is seen that tetanus is not prevented 

 or arrested by the direct current ; that is to say, tetanus is not pre- 

 vented or arrested when (as the first and second facts still show) the 

 galvanic current differs in direction from, and diminishes the power 

 of, the nerve-current. The one result is in harmony with the other ; 

 for if contraction is counteracted by imparting power to the nerve- 

 current, it is to be expected that contraction will be favoured by 

 detracting power from the nerve-current ; and certainly it is no 

 matter of wonder that contraction should be favoured by detract- 

 ing power from the nerve- current, for it is an established fact that 

 rigor mortis is coincident with absolute extinction of the nerve and 

 muscular currents, and that ordinary contraction is attended by un- 

 mistakeable weakening of these currents. It is also an established 

 fact, that muscular contraction is produced by the discharge of ordi- 

 nary statical electricity, and not by the charging and charge. Nay, it 

 is not improbable that the contractions at the beginning and ending 

 of the current, in the period of double contraction, which contractions 

 have been referred by the author to the action of induced currents, 

 may in reality be due to the withdrawal rather than to the commu- 

 nication of these currents ; for these induced currents are of moment- 

 ary duration, disappearing at the very instant of appearing, and 

 exhibiting peculiarities in disappearing which connect the disappear- 

 ance with the discharge of statical electricity, rather than with the 

 more quiet cessation of current electricity. 



And if this be so if the inverse current antagonizes and the 

 direct current favours contraction then we may in some degree un- 

 derstand how it is that contraction occurs alternately at the beginning 

 of the direct, and at the end of the inverse current. 



When the inverse current passes, there is no contraction at the 

 beginning of the current, for the influence of this current upon the 

 nerve-current is one which antagonizes contraction ; when the inverse 



