CHAPTER XII 



THE ELECTRICAL PHENOMENA OF MUSCLE 



WE have seen that the chemical processes occurring in muscular con- 

 traction lead to a transformation of energy into work and heat. 

 These changes are accompanied by electrical disturbances also. 



The history of animal electricity forms one of the most fascinat- 

 ing of chapters in physiological discovery. It dates from 1786, 

 when Galvani made his first observations. Galvani was Professor of 

 Anatomy and Physiology at the University of Bologna, and his wife 

 was one day preparing some frog's legs for dinner, when she noticed 

 that the apparently dead legs became convulsed when sparks were 

 emitted from a frictional electrical machine which stood by. Galvani 

 then wished to try the effect of lightning and atmospheric electricity 

 on animal tissues. So he hung up some frogs' legs to the iron trellis- 

 work round the roof of his house by means of copper hooks, and saw 

 that they contracted whenever the wind blew them against the iron. 

 He imagined this to be due to electricity secreted by the animal 

 tissues, and this new principle was called Galvanism. But all his 

 contemporaries did not agree with this idea, and most prominent 

 among his opponents was Volta, Professor of Physics at another 

 Italian university, Pavia. He showed that the muscular contractions 

 were not due to animal electricity, but to artificial electricity pro- 

 duced by contact with different metals. 



The controversy was a keen and lengthy one, and was terminated 

 by the death of Galvani in 1798. Before he died, however, he gave 

 to the world the experiment known as " contraction without metals," 

 which we shall study presently, and which conclusively proved the 

 existence of animal electricity. Volta, however, never believed in it. 

 In his hand electricity took a physical turn, and the year after 

 Galvani's death he invented the Voltaic pile, the progenitor of our 

 modern batteries. Volta was right in maintaining that galvanism 

 can be produced independently of animals, but wrong in denying that 

 electrical currents could be obtained from animal tissues. Galvani 

 was right in maintaining the existence of animal electricity, but 



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