File:General physiology of muscles and nerves (1881) (14591219217).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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decreasing proportion. But any required function-character,whether it is expressed by a comparison or in a table drawnup on the basis of observations, may be diagrammatically 296 PHYSIOLOGY OF MUSCLES AND NERVES. shown by a inetliod first employed by Descartes, whicli it isour present object to explain. The amounts treated may be of tbe most varied kinds :numbers, weights, degrees of warmth, tbe number of birthsor deaths, and so on. In all cases the amount may be diagram-matically shown by the length of a line. If a line of a cer-tain length represents any given amount, then double thisamount is represented by a line twice the length of theformer. It does not matter what is the standard selected;but when once selected it must not be varied in the samerepresentation. Two Hnes are drawn at right angles toeach other; from the point of section B (fig. 69) the lengthswhich are to represent the values of one series (in our case,the weights attached to the muscle) are measured off on thee^ f
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A Fig. 70. Diagrah of positive axd negative values.horizontal Hne. From each of the points thus obtained, d, h,d, d, a line is drawn at right angles to the first, care beingtaken to make its length express the expansion correspondingwith each weight respsctively. This gives the lines d B,h B, d B, d B^, By connecting these points weobtain the cirrve BB B B B x, which at a glanceshows the relation between the weight and the expansion.In exactly the same way the curve h V h h B y is pro-jected, and this represents the expansion of the active muscleby the corresponding weights. In many cases it is required to represent values of oppo-site kinds. If, for example (fig. 70), the wire a 6 is tra-versed by an electric current, then one half assumes positivetension, the other negative tension. To express this, the NOTES A2sD ADDITIONS. 297 lines which, are to represent positive tension are drawnupward, those which are to represent negative tension down-■ward, from the basal line. The figure

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