File:General physiology of muscles and nerves (1881) (14754622706).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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a frog, andis fastened into the myograph just described, it nevershortens spontaneously. If this does seem to happen, itmay safely be assumed that some accidental and un-perceived external cause has influenced it. A musclemay, however, always be induced to shorten bypinching it with tweezers, by smearing it with strongacid, or by bringing certain other external influences,the nature of which we shall presently learn, to bearupon it. Muscle, therefore, never shortens sponta-neously, but it can always be induced to do so. Thisquality of muscle enables us to produce the stateof contraction at pleasure, and to examine accm-atelythe nature and method of the conditions which giverise to it and the phenomena by which it is accom-panied. The myograph which, by means of the indicatorattached to it, marks the contraction of the muscle onthe smoked glass plate, and at the same time afiordsopportunity for measuring the extent of the contraction,will presently prove of yet greater service. But for
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2a H 30 THYSIOLOGY OF MUSCLES AND NERVES. our present purpose—which is to discover whether ornot contraction takes place under certain circumstances—it is hardly adapted. It may, therefore, be replacedby another apparatus, arranged by du Bois-E.eymondespecially for experiments during lectures, and called byhim the inuscle-telegraph. The muscle is fixed in avice; its other end is connected by a hook with athread running over a reel. The reel supports a longindicating hand to which a coloured disc is attached.The muscle in shortening turns the wheel and lifts thedisc; and this is easily seen even from a considerabledistance. A second thread, slung over the reel, sup-ports a brass vessel which may be filled with shot, so asto apply aiJy desired weight to the muscle. The influences which cause the contraction of themuscle, such as pinching or smearing with acid, arecalled irritants, and the muscle is said to be irritable,because contraction can be induced in it by these means.The irri

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