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Researches into the Effects of certain Physical and Chemical 

 Agents on the Nervous System. By Marshall Hall, 

 M.D., F.R.S., Foreign Associate of the Royal Academy 

 of Medicine of Paris, &c., &c. (With a Plate.) Commu- 

 nicated by the Author. 



Section I. On the Electrogenic Condition of Muscular Nerves. 



My object in the present paper is to detail the results of 

 an investigation of the phenomena and laws of production 

 and action of certain secondary or induced conditions of the 

 nervous system, which are effected by a Voltaic, and probably 

 by any other electric current, but persistent, after the influ- 

 ence of that current is withdrawn, and, for which I venture 

 to pi'opose a new designation. 



I have chosen that of Electrogenic, as denoting at once the 

 origin and the independence of this condition.* 



I. Introductory Observations. 



The immediate effects of the Voltaic influence on the 

 nervous and muscular structure of the frog, as well as the 

 phenomena of various Voltaic combinations of the different 

 parts of that animal, have been admirably ascertained and de- 

 scribed by Signor Matteucci ; the secondary and induced 

 electrogenic conditions of the nervous structure, which I am 

 about to describe, have not, I believe, been fully or accui'^tely 

 noticed by any experimentalist. 



In prosecuting this inquiry, I shall be led to advert to the 

 distinct portions of the spinal system, its incident or excitor 

 nerves, its centre, the true spinal marrow, and its reflex or 

 muscular nerves ; and to state the modes of electrogenic con- 

 dition or induction, with the effects or phenomena of this con- 

 dition on each of these parts of the nervous system. 



My first object in taking up this investigation was, to de- 



* This term is deri' ed from JjXexrgoi' and ynvofiai, tlie noun in the genitive 

 case, the verb in the passive voice, as in yrjyivrii, ndiXoyevris, 'jrv^iyevrji, &c., 

 and as in the recent terras, electrolytic, thermo-electric, photogenic, &.C., (phos- 

 gene (gas) ought to be photogene). With these terms, may be compared the 

 compounds of the active ytvvau with the accusative case in Scapula. 



