CHAP. XI.] MATTEUCCl'S PHYSIOLOGICAL RESEARCHES. 383 



In short, the organic actions of muscle, by which the electrical current is de- 

 veloped, may be compared to the inorganic phenomena attending its production 

 from the decomposition of metals. When a plate of metal,"* immersed in an 

 acidulated fluid, is oxidised by the oxygen of the water, and then dissolved in 

 the acid, we admit that an enormous quantity of electricity is developed 

 during this action ; we add likewise, that, just as the two electrical states are 

 disengaged, a synthesis takes place, and the effects of the previous decompo- 

 sition are neutralised. It is only by means of certain arrangements that we 

 can obtain the free electricity which is developed during chemical action. We 

 unite to the metallic plate another which is not attacked by the water, and 

 plunge this second plate also in the water. The circuit is thus established, and 

 the electric current circulates in the liquid from the metal acted on to the 

 other, and from this latter back again to the first through the metallic arc 

 of union. 



The metal acted upon in the artificial arrangement is represented, in the phe- 

 nomenon of the muscular current, by the muscular fibre ; the acidulated fluid 

 is the arterial blood. The surface of the muscle, or any other conducting body 

 not muscular fibre, but which is in contact with the muscle, represents the 

 second plate of metal, which does not suffer chemical action, and which serves 

 only to form the circuit. The direction of the muscular current is precisely 

 such as it should be, supposing the current to be, as we have represented it, 

 due to a chemical action taking place in -the interior of the muscle. 



The nervous system may act in two ways in connexion with this phenome- 

 non ; 1, as an imperfect conductor, which makes part of a circuit, but is not 

 the source of electricity; it represents the electrical state of the muscular 

 mass, interior or surface, with which it is in connexion ; and 2, it acts in the 

 conservation of the cause which disengages electricity, namely, nutrition. It is 

 fully proved, that the integrity of the nervous system and the nutrition of the 

 muscles, are closely leagued together ; but as it cannot be admitted that the 

 chemical action which takes place in nutrition is immediately arrested or 

 suspended by the cutting off nervous influence, so we must allow that the 

 muscular current may continue after the nerve has ceased to exert any control 

 over the muscle, 



The proper current of the frog does not admit of being explained upon these 

 principles. It has been supposed, as already stated, that this current is a 

 thermo-electric one, due to the unequal cooling of nerve and muscle, depend- 

 ing on the difference of evaporation in these two parts of the animal. But it 

 has been shewn that this current persists even after the removal of the nerve ; 

 and, moreover, as Matteucci remarks, a current which is sensible to a galvano- 

 meter with a long coil, which traverses thick layers of liquid, which may be 

 obtained by bringing muscle in contact with muscle, and which may be pro- 

 duced by holding animal parts in water, cannot certainly be of thermo-electric 

 origin. It has also been supposed that this current is due to an electro- 

 chemical action ; that the leg of the frog is charged with alcali or salts, whilst 

 the thigh or the lumbar nerve contains acid. But chemical analysis of these 

 parts affords no countenance whatever to this hypothesis. There are remark- 

 able points of analogy between this current and the muscular current. Mat- 



Matteucci, loc. cit. p. 124. 



