The American journal of the medical sciences . rapidly produced. There must be a certain amount of lag in the response of any muscleto an applied electro-motive force, though in the case of a healthymuscle it must be very small, and probably would have to be measuredin thousandths of a second, if not in some smaller unit. But in a de-generated muscle it would appear that this lag amounts to somethingappreciable. If, by means of a suitable commutating device, we applyvoltaic alternatives to such a muscle, and have some means of measuringthe rate of alternation at which the muscle ceases to resp
The American journal of the medical sciences . rapidly produced. There must be a certain amount of lag in the response of any muscleto an applied electro-motive force, though in the case of a healthymuscle it must be very small, and probably would have to be measuredin thousandths of a second, if not in some smaller unit. But in a de-generated muscle it would appear that this lag amounts to somethingappreciable. If, by means of a suitable commutating device, we applyvoltaic alternatives to such a muscle, and have some means of measuringthe rate of alternation at which the muscle ceases to respond to a givencurrent, we can ascertain the lag of that muscles response behind theapplied electro-motive force. It has occurred to the writer that this test might possibly give someknowledge of the condition of a degenerated muscle, and with this endin view the following apparatus was assembled : First, a rotary commutator (Figs. 1 and 2) to give voltaic every revolution of this commutator the current is reversed six Commutator. times. The pulley wheel of the commutator is four inches in diameterand is driven from a half-inch pulley on a small electric motor (Fig. 3)Current is supplied to the motor from a storage battery ; and by meansof a variable resistance the motor can be made to run at any speed fromabout iJOO to over GOOO revolutions per minute. STARR, YOUXG, MUSCLE RESPONSES. 365 The speed of the coramutatdr is recorded automatically on a chrono-graph, which may be thrown in and out of circuit at pleasure by aswitch placed within easy reach (see Fig. 3, near the base of the motor). Fir. 2.
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