AM MAI. F.LF.CTKirlTY. 



95 



these nerves that llic OfgUH :u t, it is not im- 

 possible that the. nervous influence itself is 

 accumulated in tlii'sc cells as in condensers, 

 ami tliat it is discharged at will, just as this 

 influence is accumulated iii the muscular tissue 

 to produce contraction of its fibres." It was 

 reflection on the phenomena of animal elec- 

 tricity that led Dr. Wollaston to form the hy- 

 pothesis, which he supported with so much 

 ability, of secretion in general being depen- 

 dant on electricity, conveyed by the nerves, 

 and acting on the secerning organs.* Dr. 

 Wilson Philip, also, thinks that the circum- 

 stances under which electrical action is mani- 

 fested by fishes go to the support of his theory 

 of the nervous influence being identical with 

 common and voltaic electricity. Dr. Faraday 

 says that, from the time that it was shewn that 

 electricity could perform the functions of the 

 nervous influence, he has had no doubt of their 

 very close relation, and probably as effects of 

 one common cause. To the numerous list of 

 learned observers who have speculated on this 

 interesting subject, we have to add the re- 

 spected name of Sir John Ilerschel, who 

 imaginM that the present state of electrical 

 science warrants the conjecture, that the brain 

 and spinal marrow form an electric organ, 

 which is spontaneously discharged along the 

 nerves, at brief intervals, " when the tension 

 of the electricity reaches a certain point. "f 

 Meissner, again, supposes that the blood be- 

 comes charged with electricity in the lungs, 

 dining the chemical process of respiration ; 

 that the electricity immediately traverses the 

 nerves of the lungs, and then the other parts 

 of the ganglionic system ; that hence the cen- 

 tral organs of the nervous system become 

 charged ; and that the brain, on and through 

 which the will acts, being charged, excites the 

 several organs to activity through the medium 

 of their respective nerves, along which electric 

 currents are passed.J The facts, (in addition 

 to those which have chiefly engaged our atten- 

 tion in this article,) upon which such theories 

 are built are, (1) that the muscles of an 

 animal recently dead contract when common 

 electricity passes through them, just as they do 

 when they are subject to the animal's will ; 

 (2) that voltaic electricity acts upon secreting 

 organs, so as to enable them in some degree to 

 carry on their functions after their proper nerves 

 have been cut; and (3) that the same agent 

 appears to influence powerfully the capillary 

 circulation. But, although these facts, taken 

 along with what we know of the phenomena 

 of the electricity of fishes, certainly do appear 

 to favour the views to which we have just 



* Phil. Mag. xxxiii. 488. 



t Discourse on the Study of Nat. Phil. 343. 



t Syst. der Hcilkundc. Wicn. 1832. If hypo- 

 theses such as these should hereafter be proved to 

 express the true state of the case, the electrical 

 tisht-s will become objects of great interest to the 

 physiologist, as presenting him with opportunities, 

 such as no other animals aftbrd, of studying in 

 ai'cumultitum the properties of that wonderful agent, 

 which is tlu' iiwnnti ptwer of the animal organiza- 

 tion, and a very important link in the chain of 

 causes and effects by which life is manifested. 



alluded, t'iere are yet other facts which are so 

 hostile to them as tn make it probable tlut 

 they do not express the truth. For instance, 

 the most carefully conducted experiments h,i\e 

 failed to demonstrate, the existence of electric 

 currents through muscles during their contrac- 

 tion; which, from all that is known of the 

 phenomena exhibited by electricity in other 

 circumstances, it may be presumed would not 

 have been the case had it been the immediate 

 stimulant of muscular contraction. JM. Per- 

 son has applied the poles of a galvanometer to 

 the spinal marrow without obtaining any indi- 

 cations of the existence of electrical currents 

 through its substance. The subject!! of Per- 

 son's experiments were cats, dogs, rabbits, 

 eels, and frogs. The spinal canal having been 

 opened, the piles of the galvanometer were 

 placed in communication with the anterior and 

 posterior columns of the cord. This was done 

 at different parts, after the roots of the nerves 

 had been cut. Small plates of platiua, with 

 which the wires of the instrument were armed, 

 were thrust into the cerebellum and into several 

 of the largest nerves. These experiments were 

 repeated after the animals had been placed 

 under the influence of strychnia. Hut there 

 was no certain indication of electricity ob- 

 tained, although the most delicate instruments 

 were used.* Person's experiments have been 

 repeated by Muller with the same results. 

 Messrs. Prevost and Dumas, however, slate 

 that, having armed the branches of their gal- 

 vanometer with two wires of platina, exactly 

 alike, and having plunged one of them into 

 the muscles of a frog's leg, while, with tin- 

 other, heated to redness, they touched iu 

 nerves, they saw considerable deviations of the 

 needle of the instrument follow the contrac- 

 tions of the muscles.f But seeing that the 

 electricity made manifest in this experiment 

 may have been developed rather by the con- 

 tact of the hot wire and the nerves than by the 

 nervous actions, we cannot admit that it is 

 sufficient to prove the existence of electrical 

 currents in muscles during their contraction. 

 Dr. Faraday, also, has lately experimented on 

 living muscles with the very delicate galvano- 

 meter invented by himself, but has entirely 

 failed to obtain indications of moving electri- 

 city. Negative results such as these, obtained 

 by so many practised observers, are sufficient 

 to induce us to withhold our assent from those 

 theories which make nervism identical with 

 electricity, until the whole subject shall have 

 been more fully investigated. 



As in some degree illustrative of the pheno- 

 mena of animal electricity, properly so called, 

 we must here take notice of the manifestation 

 of common electricity in animal tultstancet and 

 m living animals. 



The mere contact of heterogeneous bodies is 



* Journal de Physiol. x. 217. Some years ago 

 M. Pouillet announced that he had witnessed 

 electrical phenomena during the operation of the 

 acupuncture of muscles ; but he hat since con- 

 fessed that he was deceived. 



T Kdwards. De I'influence des agens physiques 

 sur la Vie, in Appendix. 



