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fixed to tins very light lever. Underneath the lever I have suspended a weight weighing 10 grammes, that is, about 150 grains, about the third of an ounce, which the muscle will be obliged to lift when it contracts. Then you see the sciatic nerve is stretched over these platinum wires, which we call electrodes, and the wires come from the secondary coil of our induction Fig. 30.—Diagram showing the break in the railway myograph. Current enters at d, passes along arm of brass a, having a bit of platinum at b', thence through point of screw c to e, and back to battery by g. When the plate of the railway runs across, it knocks a aside and opens current at b. machine. Here is the primary coil of the induction machine. I have interposed in its circuit this galvanic element or cell, and we will allow our railway myograph to break the circuit of the primary coil as it rushes down the railway incline. Thus when the break is opened, the opening shock will go from the secondary coil to the nerve. Now, the moment