File:General physiology of muscles and nerves (1881) (14754699276).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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uches the surface of the muscle-fibres. The nervethen represents a sort of applied arch, uniting the nega-tive cross-section and the positive longitudinal section,and a current, corresponding with the difference of ten-sion at these points of contact, passes through the nerve. This current may at the moment of its generation, i.e. on tliesudden application of the nerve, exercise an irritating effect onthe nerve and may elicit a pulsation of the muscle. This is the 210 PHYSIOLOGY OF MUSCLES AND NERVES. If the nerve of the muscle B is then irritated, either byclosing or by opening a current, by an inductive shock, byscission, by pressure, or in any other way, the muscle Ais observed to pulsate also. This is called second-ary pulsation. The explanation is easy. The muscle-current from B dairing its pulsation suffered a negativevariation. This variation took place also in that por-tion of the current which passed through the appliednerve ; and, as every nerve is irritated by sudden change
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Fig. 57 & 58. SEcoNDARr pulsation. in the strength of the current, the result was a secon-dary pulsation. A variation of this experiment is very interesting.The heart of a frog continues to beat for some timeafter it has been extracted from the body. If the nerveof a muscle is placed on this heart so as to touch itsbase and point, the muscle pulsates at every beat ofthe heart. In this case, the heart-muscle affords themuscle-current, the negative variation of which irritatesthe applied nerve and causes secondary pulsation. pulsation without metals (Zuchnni oluie Mctallc) which hasgained celebrity from the wa-itings of Volta, Humboldt, and others- SECONDARY PULSATION AND TETANUS. 211 If the nerve of one muscle is placed on a secondmuscle in such a way that no observable part of thecurrent passes through the former (as shown in thenerve of the muscle C, in fig. 58), no secondary pul-sation takes place in the muscle. If the nerve of the first muscle is repeatedly irri-tated in such a

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