THE NOBILITY OF KNOWLEDGE. 615 



The patient waiting had been rewarded, for this observation was 

 the beginning of a line of discovery which was ere long to revo- 

 lutionize the world. But Galvani was not destined to follow far the 

 new path he had thus opened. The remarkable fact observed was 

 this : The convulsions of the frog's legs could be produced without 

 the intervention of electricity, or, at least, of the one kind of electri- 

 city then known, and Galvani soon found out that the only condition 

 necessary to produce the result was, that the nerve of the frog should 

 be connected with the muscle of the leg by some good electrical con- 

 ductor. But, although Galvani followed up this observation with the 

 greatest zeal, and showed remarkable sagacity throughout his whole 

 investigation, yet he was too strongly wedded to his own theory to 

 interpret correctly the facts he observed. He supposed, to the end of 

 his life, that the whole effect was caused by animal electricity flowing 

 through the conductor from the nerve to the muscle, and his experi- 

 ments were chiefly interesting to himself and to his contemporaries, 

 from the light they were supposed to throw on the mysterious prin- 

 ciple of life. We now know that animal electricity played only a 

 small part in the plienomena he observed, and that the chief effects 

 were due to a cause of which he was wholly ignorant. 



Galvani published his observations in 1791, in a monograph enti- 

 tled " The Action of Electricity in Muscular Motion." This publica- 

 tion excited the most marked attention, and, within a year, all Europe 

 was experimenting on frogs' legs. The phenomena were everywhere 

 reproduced, but Galvani's explanation of the phenomena was by no 

 means so universally accepted. His theory was controverted in many 

 quarters, and by no one more successfully than by Alexander Yolla, 

 Professor of Physics in the neighboring University of Pavia. Volta, 

 while admitting, with Galvani, that the muscular contractions were 

 caused by electricity, explained the origin of the electricity in a 

 wholly different way. According to Yolta, the electricity originated 

 not in the animal, but in the contact of the dissimilar metals, or other 

 materials used in the experiment. This difference of opinion led to 

 one of the most remarkable controversies in the history of science, 

 and for six years, until his death in 1798, Galvani was occupied in de- 

 fending his theory of animal electricity against the assaults of his dis- 

 tinguished countryman. 



This discussion created the liveliest interest throughout Europe. 

 Every scholar of science took sides with one or the other of these emi- 

 nent Italian philosophers, and the scientific world became divided 

 into the school of Galvani and the school of Volta. Yet, so far at 

 least as the fundamental experiment was concerned, both were wrong. 

 The electricity came neither from the body of the frog nor from the 

 contact of dissimilar kinds of matter, but was the result of chemical 

 action, which both had equally overlooked. But, nevertheless, the 

 controversy led to the most important results : for Yolta, while en- 



