. Electro-physiology. Electrophysiology. 74 ELECTRO-PHYSIOLOGY CHAP. most, and provided with two levers, one of which is inserted in the upper half of the muscle just above the intersection, the other in the cartilaginous acetabulum, and if the lower half of the muscle is then excited with single induction shocks, the graphic record of the change in form of both halves of the muscle shows at once that at the moment when the lower and directly excited half begins to shorten, the upper remains pas- sively extended (Fig. 39). " But the consequent rise of the upper curve soon changes into a f
. Electro-physiology. Electrophysiology. 74 ELECTRO-PHYSIOLOGY CHAP. most, and provided with two levers, one of which is inserted in the upper half of the muscle just above the intersection, the other in the cartilaginous acetabulum, and if the lower half of the muscle is then excited with single induction shocks, the graphic record of the change in form of both halves of the muscle shows at once that at the moment when the lower and directly excited half begins to shorten, the upper remains pas- sively extended (Fig. 39). " But the consequent rise of the upper curve soon changes into a fall below the abscissa, corresponding with a shortening of the upper half of the muscle," which is brought about passive!>/ like the previous exten- sion. " As soon as the lower muscle contracts, its two ends are drawn together, it raises the weight on the one side, and extends the upper half of the muscle on the other. But the weight, once set in motion, rises in virtue of its inertia far beyond the intrinsic Fia. 39.— o, Upper; u, lower half of muscle. (Mttnzer.) height of lift ('height of projection '). At the same moment the entire muscle, including the upper half, is unloaded; the latter flies back, and shortens, thus simulating a natural contraction" ( 251). This phenomenon was actually applied by Eegeczy (30) in support of the view that the excitation process passes from one half of the muscle to the other by means of a tendinous inter- section. If all jar is avoided, extension of the upper half of the muscle only will be produced under uniform conditions, persisting so long as the lower half remains contracted. What is here said of a polymerous muscle, divided by a tendinous intersection into two parts, physiologically independent of one. another, applies equally to the two halves of a monomerous, parallel-fibred muscle, sartorius, the lower end of which is loaded and excited, a light lever being pushed through the centre of the muscle.
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