XX. Electro-physiological researches.—Eleventh series. On the secondary electromotor power of nerves, and its application to the explanation of certain electro-physio­logical phenomena

The object of this paper is to show by experiment that when a nerve is traversed by an electric current, it acquires in all its points a secondary electromotor power, and consequently becomes capable of producing in a conducting homogeneous circuit, whose extremities touch any two points of that nerve, an electric current in an opposite direction to that of the original current. This result is independent of the vital properties of the nerves, but is affected in greater or less degree by their physical condition.

XVIII. Electro-physiological researches. —Eleventh series. On the secondary electromotor power of nerves, and its application to the explanation of certain electrophysiological phenomena

The object of this memoir is to describe experiments which prove that whenever a nerve is traversed by an electric current, it acquires in all its points a secondary electromotor power, and consequently becomes capable of producing in a conducting homogeneous circuit, whose extremities touch any two points whatever of that nerve, an electric current in a contrary direction to that of the current which we shall call the exciting current. This property of nerves, which, as we shall see, is independent of their vital faculties, is nevertheless connected with their structure, and ceases when the integrity of that structure is impaired. All porous bodies, whether organic or inorganic, when saturated with a conducting liquid, are capable of acquiring a secondary electromotor power, so as to become a sort of secondary pile of Ritter; but I do not enter into an examination of these phenomena, which have been studied in their generality by other physicists, my principal aim being to determine exactly the conditions of the secondary electromotor power of nerves, in order to make a due application of these conditions to the explanation of the electro-physiological phenomena which are awakened at the opening of the voltaic circuit.

IV. Results of researches on the electric function of the Torpedo

"It has hitherto been believed that the action of the electric organ of the Torpedo was momentary only;—that it becomes charged under the influence of nervous action and discharged immediately that action ceases, somewhat like soft iron under the influence of an electric current. Such, however, is not the real state of the case. The electric organ is always charged. It may be conclusively shown by experiment that the action of that organ never ceases, and that round the body of a Torpedo, and probably of every other electric fish, there is a continual circulation of electricity in the liquid me­dium in which the animal is immersed. In fact, when the electric organ, or even a fragment of it, is removed from the living fish and placed between the ends of a galvanometer, the needle remains de­flected at a constant angle for twenty or thirty hours, or even longer. “I must here explain that in electro-physiological experiments it is highly advantageous to employ, as extremities of the galvanometer, plates of amalgamated zinc immersed in a neutral saturated solution of sulphate of zinc. This arrangement, which can be worked with the greatest facility, gives a perfectly homogeneous circuit, leaving the needle at zero in an instrument of 24,000 coils; the liquid in contact with the animal part experimented on has the greatest pos­sible conductibility while it does not act chemically on the tissue, and the apparatus is entirely free from secondary polarity.