File:General physiology; an outline of the science of life (1899) (14802854173).jpg

Identifier: generalphysiolo00verw (find matches)
Title: General physiology; an outline of the science of life
Year: 1899 (1890s)
Authors: Verworn, Max, 1863-1921 Lee, Frederic S. (Frederic Schiller), 1859-1939, ed. and tr
Subjects: Physiology
Publisher: London, Macmillan and co., limited New York, The Macmillan company
Contributing Library: Columbia University Libraries
Digitizing Sponsor: Open Knowledge Commons

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is of the heart results. While cardiac muscle is thus capable of fatigue only exception-ally, in the tissue of skeletal muscles fatigue phenomena are veryeasily induced. Fatigue has been studied most fully and most 462 GENERAL PHYSIOLOGY frequently in the cross-striated skeletal muscles of vertebrates.Since by means of the graphic method muscular movement can berecorded and its individual factors made visible, the progressivefatigue of the muscle can be studied very conveniently in thechange undergone by the curve that the contracting muscle records.Mosso (91) has done this in the living man by means of hisergograph, and has presented the results in his excellent andfascinating book entitled La Fatica. The ergograph is a smallapparatus in which the arm of a man is fastened by means of aholder, while one finger is free to move. This finger is connectedby a cord with a writing-lever, which records upon a rotating drumall the movements of the finger that take place, either voluntarily or
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Fig. 236.—Mossos-ergograph. (After Mosso.) involuntarily as the result of electrical stimulation. A weightcan be hung upon the cord, and thus the work performed by theflexor muscles of the finger can be changed at will (Fig. 236).By means of this apparatus it can be shown very clearly that, withthe stimulating induction-shocks remaining constant in intensityand following each other at equal intervals, the work performedby the muscles constantly decreases, and finally becomes equal tozero. This is expressed in the curve of contraction, which givesonly the extent of the contraction, by a constant decrease in theheight of the lift (Fig. 237). After a course of contractions itrequires considerably stronger stimulation to produce further con-traction of the fatigued muscles equal in height to that at thebeginning. The details of the changes are more readily visiblewhen the successive contraction-curves of a frogs leg are recordedover one another upon a myograph from the beginning of the

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