American journal of physiology . The subject of the experiment contracted his muscles rhythmicallyevery three seconds. The signal for contraction was the sound of ametronome beating every half contractions were recorded bymeans of Mossos ergograph and wereregistered on a revolving drum. Eachcontraction was communicated by therecording lever of the ergograph to aCzermak electric double lever. Thereader may be reminded that this mostuseful piece of mechanism (Fig. i) wasdesigned to record the limits of oscil-lation of a moving body without beingotherwise affected by the movements ofth
American journal of physiology . The subject of the experiment contracted his muscles rhythmicallyevery three seconds. The signal for contraction was the sound of ametronome beating every half contractions were recorded bymeans of Mossos ergograph and wereregistered on a revolving drum. Eachcontraction was communicated by therecording lever of the ergograph to aCzermak electric double lever. Thereader may be reminded that this mostuseful piece of mechanism (Fig. i) wasdesigned to record the limits of oscil-lation of a moving body without beingotherwise affected by the movements ofthe body. By it an electric current canbe either made or broken at the momentwhen the movement has reached its fullextent. It consists of two levers (C) and(I) (Fig. 2), each connected with one poleof a battery (F). Both levers move onthe same axis (H). The first lever (C) is U-shaped and freely embraces the second lever. The latter (I) is stationary, except1 Bowditch and Warren : Journal of physiology, 1890, xi, p. Figure i. Reinforcement of Voluntary Muscular Contractions. 337 when either elevated or depressed by the action of the first. Eacharm of the first lever can be made either a conductor or a noncon-ductor by means of small screws (b and C), tipped with platinum orivory respectively. This lever is connected with the ergograph (K) at L. A movementof the recording arm(A) of the ergograph(K), which is connect-ed with the long or U lever (C) at L,brings one of the armsof the U into con-tact with the indiffer-ent, i. f., stationarylever I. Should thisbe the arm carry-ing the ivory-pointedscrew no connectionis made, but if it bethe arm with the plat-inum-pointed screwthe current is at oncecompleted. By meansof this instrument andan automatic short-circuiting key (E), which it was subsequently found necessary tointroduce, the stimuli were controlled in a definite manner. Thus,when A was depressed or in a position of rest, /. c, the position itoccupied when the m
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