442 ELECTRICITY IN THE PHENOMENA OF ANIMAL LIFE. 



present, to a single remark on this point — already proved to be true — 

 namely, that manifestations of nerve action are always accompanied by 

 variations of electrical condition. 



I will not enlarge further upon these questions, important as they 

 are, so as not to go beyond the plan of a merely general statement of 

 views. 



No one among- yon, moreover, can have overlooked the great inter- 

 est of the researches of which these points will form the subject in the 

 new institute. 



IV. — OF TUK PART PLAYED BY Tin': NERVES IN THE PHENOMENA OF STIMULATION. 



Muscle and nerve respond to stimulation of mechanical, thermic, 

 chemical, or electrical origin, but the last of these is attended with 

 especially remarkable results. 



Electrical influence is in fact by far the most powerful and extended 

 in its effect, whether it be applied directly to the muscular tissue or, 

 above all, if it be applied to a nerve. 



On the one hand, if a muscle be directly stimulated by a shock, a 

 drop of acid, or a prick with a sharp point, we produce but a limited 

 local effect, while, on the contrary, if we act through the medium of a 

 nerve we call forth generalized effects, whatever be the stimulus made 

 use of, and it is the whole muscle that contracts as if each of its parts 

 were electritied. 



To obtain the same result without having- recourse to a nerve as 

 medium it would be necessary to apply the stimulus simultaneously to 

 all the elementary fibers of the muscle. 



These facts have a double bearing': they seem to justify the idea of 

 attributing- to the nerves the jiart of conductors, and show also that 

 electricity is the form of energy which lends itself better than any other 

 to ijropagation to a distance and to distribution in the living- organism. 



v. — OF MUSCULAR CONTRACTILITY. 



Although stimulation gives rise to electrical manifestations it does not 

 follow that the appearance or presence of electricity is necessarily 

 dependent upon the occurrence of external stimulation. 



I am much rather inclined to believe that the physiological electric 

 battery is always in a state of activity, and that a muscle works — that 

 is to say, gives out energy produced by this battery — even when it 

 accomplishes no external work. 



A muscle is an elastic body, more or less stretched, capable of being- 

 progressively contracted by the electric current up to the point of i)ro- 

 duciug an external mechanical effect. As the current diminishes the 

 muscle relaxes; as the current increases it contracts, and we may say 

 that its Umus, or intensity of contraction, is some function of the 

 quantity of electrical energy employed. 



