550 PHILOSOPHICAL TRANSACTIONS. [aNNO 1795. 



It is known that, if a muscle and its nerve be covered with two pieces of the 

 same metal, no motion will take place on connecting those pieces, by means of 

 one or more different metals. After making this experiment one day, I acci- 

 dentally applied the metal I had used as the connector, and which I still held in 

 one hand, to the coating of the muscle only, while with the other hand I touched 

 the similar coating of the nerve, and was surprised to find that the muscle was 

 immediately thrown into contraction. Having produced motions in this way 

 sufficiently often to plaee the fact beyond doubt, I next began to consider its re- 

 lations to other facts formerly known. I very soon perceived, that the imme- 

 diate exciting cause of these motions could not be derived from the action of the 

 metals on the muscle and nerve, to which they were applied; otherwise it must 

 have been admitted, that my body and a metal formed together a better 

 conductor of the exciting influence than a metal alone, the contrary of which I 

 had known, from many experiments, to be the case. The only source therefore 

 to which it could possibly be referred, was the action of the metals on my own 

 body. It then occurred to me, that a proper opportunity now offered itself of 

 determining, whether animals contribute to the production of this influence by 

 means of any other property than their moisture. With this view, I employed 

 various moist substances, in which there could be no suspicion of life, to con- 

 stitute, with one or more metals, different from that of the coatings of the 

 muscle and nerve, a connecting medium between those coatings, and found that 

 they produced the same efl'ect as my body. A single drop of water was even 

 sufficient for this purpose; though in general the greater the quantity of the 

 moisture which was used, the more readily and powerfully were contractions of 

 the muscle excited. But if the mutual operation of metals and moisture be fully 

 adequate to the excitement of an influence capable of occasioning muscles to 

 contract, it follows, as an immediate consequence, that animals act by their 

 moisture alone in giving origin to the same influence in Galvani's experiments, 

 unless we are to admit more causes of an effect than what are sufficient for its 

 production. 



Before I dismiss this part of my subject I may mention that being in posses- 

 sion of a method to determine what substances are capable, along with metals, 

 of exciting the influence, I made several experiments for the purpose of ascer- 

 taining this point. I found, in consequence, that all fluid bodies, except mer- 

 cury, that are good conductors of electricity, all those at least which I tried, 

 can with the aid of metals produce it. The bodies I tried, beside water, were 

 alcohol, vinegar, and the mineral acids; the last both in their concentrated 

 states, and when diluted with various portions of water. Alcohol however 

 operated feebly. On the other hand, no fluid, which is a non-conductor of 

 electricity, would assist in its production: those on which the experiment was 



