ELECTRO-PHYSIOLOGY. 315 



been attributed by the pliysiologists of Germany to a particular state of the 

 nerve, with which we shall occupy ourselves further on, and which they term 

 electro tonic. Before acquiescing in that hypothesis, it would have been proper 

 to inquii'e what influence may be exerted by the products of the electrization 

 collected on the nerve in contact with the electrodes upon the composition, and 

 hence upon the physiological properties of the stimulating substances used by 

 Pfluger. Moreover, we have found that the effects of the secondary electro- 

 motor power of the nerve extend beyond the points touched by the electrodes. 

 Thus, between the portion of the nerve outside of the positive electrode, and the 

 points touched by that electrode, there is a secondary current in the nerve in the 

 direction of the current of the battery. Beyond the negative electrode also 

 there is a secondary current, which has been found much stronger than that 

 produced beyond the positive electrode, and which is also directed like the cur- 

 rent of the battery. The origin of these currents and their direction is under- 

 stood without difficulty, when we remember that they depend on the currents 

 excited between the portions of the nerves which we will term neutral, and the 

 points which, by having been in contact with or very near the electrodes, ai"0 

 bathed, one with an acid; the other with an alkaline liquid. These secondary 

 electro-motor powers outside of the poles may well intervene in the effects 

 observed by Pfluger. 



After having explained, perhaps somewhat too difi'usely, the application of 

 the secondary electro-motor power of the nerves to the electro-physiological 

 phenomena which are excited at the opening of the circuit, I shall proceed to 

 speak briefly of the knowledge we possess, imperfect though it be, respecting 

 the action of the current in the muscles alone, in the central parts of the ner- 

 vous system, and upon the nerves of the ganglionic system. 



When a current or a discharge is made to pass through a muscle, contrac- 

 tion is excited, and this takes place, as is natural, independently of the direction 

 of the current. This contraction is sometimes persistent : thus, wheu the dis- 

 charge of a jar is made to pass through the gastrocnemian detached from a 

 living frog, this muscle is seen to be shortened by even one-fourth or more of 

 its length and to remain shortened. We might say that the parts of a muscle, 

 when the nervous action is extinguished or quasi extinguished, tend to approach 

 one another, and, once in this condition, remain so, as occurs after death in re- 

 gard to the cadaveric rigidity. 



I have already said that Chauveau has, in late times, varied the experiments 

 made on the muscles by applying the inducted current on the muscular mass, 

 and has found that the greater and more persistent contraction always occurs in 

 contact with the negative electrode. We have explained this phenomenon as 

 far as is yet in our power, by attributing it to the action of the direct cuiTent 

 on the nerves of this muscular mass. 1 will further recall that the contractions 

 excited by the current in the muscles of a frog killed with the poison of curare, 

 and the nerves of which have lost all trace of excitability, prove that the mus- 

 cular fibre alone, independently of the nerves, contracts under electricity as 

 under other stimulants. 



Many years since Longet and I studied the action of the electric current on 

 the spinal radicles ; that is, on those simple nerves which, according to the dis- 

 covery of Charles Bell, possess separately either the property of exciting con- 

 traction or that of occasioning pain when they are irritated. A long series of 

 experiments, which were afterwards verified in Germany and elsewhere, con- 

 ducted us to results which were chiefly noticeable for being opposed to those 

 set forth in our first proposition, which are obtained in the mixed nerves. In 

 effect, by operating with the direct current on the anterior radicles, no contrac- 

 tion was obtaining at the closing, as there was at the opening of the circuit ; 

 with the inverse current contraction takes place at the closing and none at the 

 opening. We are now able to say that this anomaly is removed in consequence 



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