M. Matteucci's Researches on Electro-Physiology. ^^l 



of an electric current traversing the nerves of an animal, de- 

 pend upon the modification which the excitability of the nerve 

 has experienced by the passage of the current, according to 

 its direction. The same cause explains the voltaic alterna- 

 tions, /. e. the muscular contractions excited by a current, 

 which is made to traverse a nerve in a contrary direction to 

 that in which it had ceased to produce any effect. 



In this first extract I shall confine myself to communicating 

 to the Academy a result which I regard as fundamental to the 

 theory of electro- physiological phaenomena. By a very simple 

 experiment, and one which is easily repeated, J have shown 

 that an electric current which traverses a muscular mass in 

 the direction of its fibres, and consequently in a direction 

 which is normal or oblique to that of the ultimate nervous 

 ramifications which are distributed through it, developes in 

 these filaments a nervous current, the direction of which varies 

 according to that of the electric current, relatively to the ra- 

 mification of the nerve. This law is the same as that which 

 establishes the relation between the direction of the nervous 

 current and the position of the contrary electric conditions in 

 the organ of electric fishes ; in other words, it is the reaction 

 of electricity upon the nervous force. In discovering a new 

 analogy, and that the most intimate possible, between the 

 electric discharge of fishes and muscular contraction, I have 

 shown that, just as in the electric apparatus of the torpedo, 

 the nervous current developes the two electricities in a deter- 

 minate direction, according to its own direction. In a mus- 

 cular mass the two electric states, diffused through the elements 

 of its fibres, produce a current, the direction of which, varying 

 with that of the electric current, is established, like the direc- 

 tion of the discharge in the torpedo, by that of the nervous 

 current which excites it. I have taken every pains to establish 

 by experiment this result, which I shall henceforth consider 

 as the foundation of the theory of electro- physiological phae- 

 nomena. Whatever may be the nature of the nervous force, 

 of which we are ignorant, as of that of the other great natural 

 agents, it is a fact that this force is propagated in the nerves 

 sometimes from the brain to the extremities, sometimes in a 

 contrary direction. It is entirely independent of hypothesis, 

 and, in fact, in accordance with experiment to admit, that in 

 the act of muscular contraction excited by the action of the 

 will or by the stimulation of the nerve, a nervous current is 

 propagated in the direction of the ramification of the nerve : 

 on the other hand, the nervous current follows an opposite 

 direction, when sensation is experienced by the stimulation of 

 the extremities of the nerve. 



