TRANSACTIONS OF THE SECTIONS. 79 
have perused this little volume, the name of the electrotonic state of the nerves will 
be familiar. I have ventured so to call the altered condition of the nerve which is 
induced by any electric current pervading any portion of it, however short, and 
which denotes its presence by a most striking change in the electromotive action of 
the nerve. The nerve, when in its natural state, produces electric currents accord- 
ing to the law of the antagonism of the longitudinal and transverse section, the 
former one being positive, the latter negative. The nerve, when in the electrotonic 
state, in addition to its usual electromotive action, produces electric currents accord- 
ing to the law of the voltaic pile. Every portion of nerve, however short, acquires 
an electromotive power such as to produce a current in the direction of the exciting 
current. This new condition of the nerve begins and ends as soon as the exciting 
current itself. I have endeavoured to account for it in the following way. The 
ordinary nervous current I consider as being produced by peripolar groups of dipolar 
electromotive molecules. According to Grotthuss’s well-established theory, the ex- 
citing current may decompose these groups, so as to make all the dipolar molecules 
turn their positive poles in that direction in which the current goes. If it be ad- 
mitted that this new arrangement extends with decreasing regularity over the whole 
length of the nerve, all the phenomena of the electrotonic state of the nerves could 
easily be explained. : 
In the second volume of my large book, I have stated that the muscles do not ex- 
hibit the phenomena of the electrotonic state. Indeed no change of the electromo- 
tive action of the muscle is perceived, when that portion of it which extends beyond 
the ends of the galvanometer is submitted to a constant electric current. Neverthe- 
less, I have succeeded in discovering a mode of action of the electric current on the 
muscles, which undoubtedly corresponds to that action of the current on the nerves 
which I have called their electrotonic state. 
If a muscle, while in the state of life, is submitted to a strong electric current, of 
any kind whatever, and if directly afterwards it be placed in the circuit of the gal- 
vanometer, the very portion of it which was comprised between the electrodes is 
found to have acquired a new electromotive power, such, indeed, as to produce,a 
current in the direction in which it was pervaded by the extraneous current. This 
new electromotive power is the greater according to the intensity of the extraneous 
current. It rapidly decreases so as to become insensible after a certain lapse of time, 
the length of which, of course, depends on the original amount of the electromotive 
power induced, as well as on the sensitiveness of the galvanometer employed. 
This new effect produced on muscles by the electric current is quite different from 
that which was discovered by Peltier, who found that muscles, when for a long 
time exposed to an electric current, acquire an electromotive power in the contrary 
direction to that in which they were pervaded by the current. These two effects, 
that observed by Peltier, and that now denoted by myself, both coexist, so as partly 
to counterbalance each other. But the contrary electromotive power, induced in 
muscles by electric currents, is analogous to that which is engendered by passing a 
current through metallic electrodes immersed in any electrolytic liquid. On the 
contrary, the electromotive power, which keeps the same direction as the current 
by which it was induced, owes its origin to the peripolar groups of dipolar electro- 
motive molecules in the muscles being decomposed by the current, and the dipolar 
molecules having their positive poles turned with more or less regularity in that 
direction in which the current goes. 
The electric current, therefore, acts in the same way on both nerves and muscles, 
viz. it decomposes the peripolar groups, and forces the dipolar molecules into a 
certain arrangement different from the natural one. In the nerves this preter- 
natural arrangement extends on either side of the portion submitted to the current, 
and even, though with decreasing regularity, over the whole length of the nerve, 
but it vanishes as soon as the exciting current itself. In the muscles, on the con- 
trary, the preternatural arrangement does not extend to any sensible degree beyond 
the portion immediately acted upon by the exciting current; but, instead of it, the 
arrangement continues to prevail a certain time after the exciting current has ceased. 
Hence it appears that the production of the new electromotive power in a nerve 
and that in a muscle, by means of an electric current passed through their substance, 
