Electro-physiology . electrophysiolog02bied Year: 1896-98 232 ELECTRO-PHYSIOLOGY CHAP. however, in the optic nerve of the fish (Ktihne, 9), where the fibres have no constrictions, and also in non-mednllated nerve (Bieder- inann, 3), although in a less marked degree, so that there is no adequate reason for assuming definite anatomical boundaries within the continuity of the axis-cylinder, at which the process of mortification shall be arrested. If the fact that the separate cell-individuals in cardiac and smooth muscle are directly united by plasma-bridges is of universal application, the cons
Electro-physiology . electrophysiolog02bied Year: 1896-98 232 ELECTRO-PHYSIOLOGY CHAP. however, in the optic nerve of the fish (Ktihne, 9), where the fibres have no constrictions, and also in non-mednllated nerve (Bieder- inann, 3), although in a less marked degree, so that there is no adequate reason for assuming definite anatomical boundaries within the continuity of the axis-cylinder, at which the process of mortification shall be arrested. If the fact that the separate cell-individuals in cardiac and smooth muscle are directly united by plasma-bridges is of universal application, the consequences of renewing the section can only indicate that the death-process is arrested at some distance from the cut surface, without confining it within preordained anatomical barriers. Nerve, like muscle, can be excited by its own demarcation current. The facts relating to this subject have been familiar since the days FIG. 201.—Excitation of nerve by its own current. of Galvani, and have more especially been investigated by Kiihne and Hering (11). Galvani introduced the nerve of a rheoscopic leg into an open circuit, and allowed the nerve of another leg, completely isolated from the first, to fall upon the circuit, in such a way that the cross-section of the first nerve formed one of the two points of contact. Both legs twitch in a successful experi- ment. Du Bois-Reymond laid the central end (transverse and longitudinal sections) of a sciatic nerve, still connected with the leg, across the pads of his zinc trough-electrodes, making and breaking the nerve current by means of a mercury key. ' The leg twitched at closure and at opening, in some cases on breaking the circuit only.' Du Bois-Reymond subsequently simplified this experi- ment by placing two long pads of filter-paper saturated witli salt solution close together upon an insulating stage, and laying acr< iss them the long and transverse sections of the rheoscopic nerve.
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