ACTION OF INTERRUPTED AND CONTINUOUS CURRENTS. 177 



This attempt having produced no result, I thought that a more 

 powerful and more constant current might diminish the excita- 

 bility of the human nerves ; and I then had recourse to a battery 

 composed of thirty of Bunsen's pairs, a little weakened by previous 

 use. Afterwards I employed a Daniell's battery of from thirty to 

 fifty elements. In all these experiments, I took care to avoid the 

 occurrence of contraction on completion of the circuit, by proceed- 

 ing in the way formerly described. (See note to page 12.) After 

 twenty or thirty minutes of action of the continuous current from 

 these batteries, in whatever direction, I was unable to discover 

 that the sensibility of the nerves had diminished. The contrac- 

 tions of the muscles supplied by the nerves were quite as ener- 

 getic, under the influence of an intermittent current, after, as 

 before the experiment ; the sensibility was not modified, and the 

 power of voluntary movement was not diminished. 



Although I was unable to diminish artificially the excitability of 

 human nerve, I had at least occasion to observe certain instances 

 of paralysis, in which the nerves and even the muscles had in part 

 lost their excitability. In these cases again, the inverse con- 

 tinuous current acted no more upon the contractility, than did the 

 direct continuous current upon the sensibility. Neither of these 

 currents abolished the excitability of nerves already affected, and 

 through which they were made to pass for a considerable time. 



To sum up, in a man in normal condition: 1. a continuous 

 current passed through a nerve, during from twenty to thirty 

 minutes, did not appear to me to diminish its excitability ; 2. when 

 I directed a continuous current, centrifugal or centripetal, upon a 

 nerve of normal excitability, or upon a nerve the excitability of 

 which was diminished by certain forms of paralysis, I observed 

 always the customary phenomena, namely, contractions and sensa- 

 tions ; neither the one nor the other of the two (direct and inverse) 

 currents ever acted, in an appreciable manner, upon either the 

 sensibility or the contractility separately.^ 



These results caused me real disappointment : since I had ex- 

 pected to obtain, in man, the phenomena described by Marianini, 

 Mobili, Matteuci, and their predecessors; and concerning which 

 the experiments made upon animals seemed to me to be entirely 

 conclusive. 



It will be said, without doubt, that if I had directed upon human 

 nerves a more intense current, I should have been able to diminish 



' I formulated almost the same con- periments, to diminish the irritability of 

 elusions in a memoir presented in 1848 to : nerves, by subjecting them to the influence 

 the Academie des Sciences. But at that i of a powerful continuous current, 

 time I had not endeavoured, in my ex- | 



N 



