230 ELECTRIC CURRENT. LECT. XII. XIII. 



by a reflected action, produces contractions of muscles not 

 supplied by the nerve irritated by the current. We may, 

 therefore, say, in the language of Dr. Marshal Hall and 

 other modern physiologists, that the electric excitation of a 

 nerve which was at first centripetal, is transformed into a 

 centrifugal one. 



Effects on dead Animals. Hitherto I have demonstrated 

 the laws of the action of the electric current on the nerves 

 of a living animal. I must now speak of this action on the 

 nerves of animals which have been recently killed. 



By submitting recently killed rabbits, prepared as in the 

 preceding experiments, to the influence of a single element, 

 we obtain the contraction of the inferior muscles, at the 

 moment when the circuit of the direct current is closed, and 

 when that of the inverse current is interrupted. By acting 

 with a more powerful battery, the contractions of the same 

 muscles take place as well as when the current begins to 

 circulate as when it ceases, whichever its direction may be. 

 After it has continued to pass for a certain time, contractions 

 no longer ensue, except at the commencement of the direct, 

 or at the cessation of the inverse current. 



These phenomena may be verified on all animals, but 

 they are most easily shown in the frog. 



I have here one of these animals, prepared according to 

 Galvani's usual method, and from which the bones of the 

 pelvis, and the lumbar vertebra have been removed. This 

 frog is placed astride with one foot in one glass full of 

 water, and the other foot in another glass of water. 



When I plunge the two conductors of a pile into these 

 glasses, you will at first observe that the frog will leap out ; 

 and if we retain it forcibly in its place, contractions take 

 place in both legs both when opening and closing the cir- 

 cuit, and, consequently, in the limb in which the current is 

 .direct, as well as in that in which it is inverse. But if we 



