File:General physiology of muscles and nerves (1881) (14775352354).jpg

Identifier: generalphysiolo00rose (find matches)
Title: General physiology of muscles and nerves
Year: 1881 (1880s)
Authors: Rosenthal, I. (Isidor), 1836-1915
Subjects: Physiology Muscles Nerves
Publisher: New York, D. Appleton and company
Contributing Library: Columbia University Libraries
Digitizing Sponsor: Open Knowledge Commons

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for example, care is taken that the muscle retainsits form unaltered, by fastening it in a suitable clamp,and if this muscle is then irritated into activity, thecurrent decreases in exactly the same way as when theexperiment is carried out as before described. It is an especially interesting fact that this samephenomenon may also be observed in the muscles ofliving and uninjured men. It is very hard to provethat the electric action of muscles of living animalsin their natural position is exactly the same as that ofmuscles when extracted; but the fact that on contrac-tion exactly the same electric processes occur in muscleswhether they are in their natural position or have been NEGATIVE VARIATION OF THE MUSCLE-CXKRENT. 205 extracted is quite certain. E. du Bois-Eeymond showedthis in the human subject in the following Avay. Theends of the wire of the multiplier are connected withtwo vessels filled with liquid, and the index finger ofboth hands is chpped in these vessels, as in fig. 56.
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Fig. 56. Dkflectiox ov the magnetic needle by the avii.l. A rod arranged in front of the vessel serves to steadythe position of the hands. Currents are then presentin the muscles of both arms and of the breast, which,since the groups of muscles aie symmetrically arranged,cancel each other, acting one on the other. If for anyreason any current remains uncancelled, it may becompensated in the way before described. When allis thus arranged, and the man strongly contracts the 206 PHYSIOLOGY OF MUSCLES AND NERVES. muscle of one arm, the result is an immediate deflec-tion of the multiplier, which indicates the presence ofa current ascending in the contracted arm from thehand to the shoulder. If the muscles of the other armare contracted, a deflection occurs in the opposite direc-tion. We are, therefore, able by the mere power of thewill to generate an electric current and to set the mag-netic needle in motion. Summing up all that has been said, it appears that,during muscular contraction, t

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