American journal of physiology . er (D) thatrecorded upon the movingsurface of a kymograph theextent of the movement ofthe spring. The lever wasso arranged as to permit aFigure i. magnification of the springs movement when such a pro-cedure was thought advisable. This magnification was often neces-sary with heavy springs in order that a more accurate reading of thecurves—/. c. of the extent of movement of the spring — could beobtained. The lever was made of aluminum and very light. It waspointed with a strip of tinsel. Had the lever been left in this simplecondition the inertia of motion might
American journal of physiology . er (D) thatrecorded upon the movingsurface of a kymograph theextent of the movement ofthe spring. The lever wasso arranged as to permit aFigure i. magnification of the springs movement when such a pro-cedure was thought advisable. This magnification was often neces-sary with heavy springs in order that a more accurate reading of thecurves—/. c. of the extent of movement of the spring — could beobtained. The lever was made of aluminum and very light. It waspointed with a strip of tinsel. Had the lever been left in this simplecondition the inertia of motion might have been sufficient to cause adistortion of the actual contraction. To overcome this possible sourceof inaccuracy the lever was held back by a light spring (E) which wasextended by each movement of the lever. This spring was so weakin comparison with the extension springs against whose force themuscle worked, that the work accomplished could be and was en-tirely disregarded in the calculations. The force exerted to stretch. Force of Voluntary Muscular Contractions. 355 this small spring was never more than per cent of the total forceexerted, and often this per cent decreased to O. i. The muscle employed was the flexor sublimis of the middle fingerof the left hand. The arm was extended in a supine position, theindex and the third fingers were placed in closely fitting brass tubesto keep the hand fixed. Straps were placed about the wrist and palmto prevent lateral movements of the arm and hand. The cordattached to the spring was fastened to the*finger by means of a metalsplint. The two parts of the splint were made to constrict the fingeras little as possible; the dorsal part was furnished with an adjust-able hook that enabled the experimenter to keep the muscle leverageconstant.^ The constancy of this condition seems not to have beenconsidered in the work of Mosso, Lombard, and Maggiora. In theirexperiments a leathersling was fitted to thefinger and to it theweight cor
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Keywords: ., bookautho, bookcentury1800, bookdecade1890, booksubjectphysiology
