94 



ANIMAL ELECTRICITY. 



of common and voltaic electricity are pro- 

 duced by animal electricity; which appears 

 to be sufficient to prove that the latter is as 

 much a peculiar power distinct from these as 

 are the agents called magneto-electricity and 

 thermo-electricity. Perhaps, however, what 

 we at present regard as so many powers dif- 

 fering from one another in their natures, may 

 be merely modifications of the same power, 

 varied in its sensible properties by changes in 

 the circumstances under which they are mani- 

 fested. This latter view is that taken by Dr. 

 Wilson Philip, who holds that Animal Elec- 

 tricity is just common electricity modified in 

 its properties by those of life, under the in- 

 fluence of which it operates in the living 

 animal. 



Sir Humphry Davy thought he saw a 

 stronger analogy between common and animal 

 electricity, than between voltaic and animal 

 electricity, but concluded that the latter would 

 be found by more extended researches than 

 he was able to make to be " of a distinctive 

 and peculiar kind."* Cavendish, on the other 

 hand, believed that there is a complete identity 

 between common electricity and that of fishes. 

 And this he laboured to prove by imitating 

 several of the peculiarities of the discharge of 

 the torpedo by a particular arrangement of 

 small Leyden jars, forming a battery, from 

 which the electricity was discharged in large 

 quantity but of low intensity .f Others, again, 

 have attempted to trace a certain resemblance 

 between the structure of the electrical organs 

 of the torpedo and the formation of the voltaic 

 pile, " inasmuch as they are formed of alter- 

 nate layers of moistened conductors of dif- 

 ferent natures, to wit, of membranous parti- 

 tions, and of gelatinous and albuminous fluid." 

 (Tiedemann.) They suppose that the nerves, 

 being spread over one side of the transverse 

 partitions of the cells, produce opposite states 

 of electrical tension on the two sides of the 

 partition. In the present imperfect state of 

 electrical science, all such hypotheses are un- 

 satisfactory. 



The only conclusions which, in our opinion, 

 can be legitimately drawn from the accumu- 

 lated facts on the subject are that the shock 

 given by electrical fishes is caused by an agent 

 closely allied in its nature to common elec- 

 tricity and other like powers ;\ and that the 

 developement and discharge of this agent are 

 strictly dependent on the integrity of the ner- 

 vous communication between certain peculiar 

 organs and the great nervous centres. 



It is evident that the nervous system plays 

 a very important part in the electrical function. 

 But whether its influence merely stimulates 

 the electrical organs to do what their organic 



* Philos. Trans. 1829. 16. 



t Philos. Trans. 1776. 196. 



J The latest experiments on the subject, with 

 which we are acquainted, are those of Messrs. 

 Becquerel and Breschet, reported to the Academy 

 of Sciences in October, 1835, (Ann, des Sciences 

 Nat. n. s. iv. 253,) which seem to have been per- 

 formed with great care. The experimenters com- 

 pletely satisfied themselves that the shock of the 

 torpedo is the result of an electrical discharge. 



structure renders them capable of doing, or 

 really supplies them with a stream of the im- 

 ponderable agent which they accumulate, and 

 then, under voluntary impulses, discharge, is 

 still a point for further investigation. In the 

 structure of the electrical organs, we do not 

 see any arrangement such as researches in elec- 

 tricity artificially developed lead us to believe 

 fitted either to produce or to accumulate elec- 

 tricity. But this is in itself no reason why 

 we should conclude that the organs have not 

 such powers. It seems more in accordance 

 with what we know of the actions of other 

 parts of the animal frame, to believe that they 

 do possess such powers. But if the elec- 

 trical organs, by their organic structure, be 

 fitted to develope and to discharge electricity 

 under the nervous influence, just as a gland 

 secretes its peculiar fluid and its ducts eject it, 

 why (it may be asked) are the nerves going to 

 these organs of so very great a size compared 

 with the same parts in other organs of similar 

 bulk and very energetic action ? Is their sub- 

 jection to the will of the animal sufficient to 

 account for the difference ? or does it indicate, 

 as some physiologists maintain, that the ner- 

 vous influence does more in this case than 

 merely supply the vital stimulus such as is 

 received by all other organs in common ? In 

 other words is the agent discharged by the 

 fish as electricity first developed in the ner- 

 vous centres, and only accumulated in the 

 electrical organs ; and is this agent identical 

 with common nervism ? To these questions 

 we cannot yet give a satisfactory reply. They 

 point the way to some very interesting and im- 

 portant fields of investigation, and cheer us 

 with the hope of considerably extending our 

 acquaintance with the physiology of the nerves, 

 on the supposition that the phenomena of ani- 

 mal electricity shall one day be proved to be 

 owing to an accumulation and discharge of the 

 very "same agent that causes contraction of 

 muscles, &c. Such a view appears to have 

 been taken of this subject by Sir H. Davy 

 when he remarked,* " there seems a gleam of 

 light worth pursuing in the peculiarities of 

 animal electricity, its connexion with so large 

 a nervous system, its dependence on the will 

 of the animal, and the instantaneous nature 

 of its transfer, which may lead, when pursued by 

 adequate inquirers, to results very important for 

 physiology." Treviranus, in 1818, suggested the 

 likelihood of the power concerned in the ma- 

 nifestation of electrical phenomena by animals, 

 being one of those on which continuance of 

 life in general depends. " Perhaps," said he,f 

 " it is the same power which enables the tor- 

 pedo to give electric shocks that is the imme- 

 diate cause of the contraction of muscular 

 fibres." The same hypothesis is thus ex- 

 pressed by Carus.J " Numerous nerves are 

 distributed upon the cells of the electrical 

 organs, and as it is through the agency of 



* Philos. Trans. 1828. 

 t Biologie. v. 141. 



| Traite element, d'anat. oomp. 2d edit. i. 392. 

 (French translation by Jourdan.) 



