Vital and Physical Motion. ,139 



occasion to call in the aid of a vital property of irrita- 

 bility. Indeed, it is difficult to see how such a property 

 could act so as to bring about the double movement of 

 protrusion and retraction which has to be accounted for 

 in this particular form of vital motion. 



Muscular movements, like amaeboid movements, are 

 also in the main resolvable into electrical movements, 

 but here the electricity at work is more than that which 

 belongs to all terrestrial bodies equally. 



By the galvanometer it is made evident that there is 

 a current, called the ' muscle-current,' in living muscle 

 which is not to be detected in muscle that has passed 

 into the state of rigor mortis, and also that this current 

 disappears in great measure, or suffers a ' negative varia- 

 tion,' when a living muscle passes from the state of rest 

 into that of action. By the electrometer it is made 

 evident that there is in living muscle a charge which 

 disappears in great measure when the state of rest 

 changes into that of action, and which is absent al- 

 . together in rigor mortis a double charge which is + in 

 the part from which, and in the part to which, the 

 muscle-current sets. And further what may not be so 

 clearly made out either by galvanometer or by the electro- 

 meter, by a ' rheoscopic limb,' or frog's hind leg prepared 

 in a particular way, it is made evident that muscular con- 

 traction is, as Matteucci pointed out, accompanied by an 

 electrical discharge analogous to that of the Torpedo. 

 Many experiments with Thomson's new quadrant elec- 

 trometer, made by myself, justify me in saying what I 

 have said about the electrometric facts, and in coming to 

 the conclusion that the manifold operations of voltaic 

 electricity in muscular motion are to be explained, not by 

 the action of the current, but by that of the charges, and 

 discharges (instantaneous currents of high tension on 



