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23 repeated, with, however, some modification in the details.

The electric arrangements were as follows : — A constant difference of potentials was maintained by means of a galvanic battery between the terminals of the primary series of coils of a Thomson's Slide Resistance. Two flexible insulated wires, the free ends of which terminated in platinum needles, and were used as the electrodes, were connected, the one to the zero end of the primary series of coils, and the other to the sliding contact of the secondary coils. By suitably moving the sliding contacts, any desired difference of potentials could thus be established between the electrodes.

Experiment VII.

A frog (Rana tigrina) was killed mechanically at 12.18 P.M., but reflex action continued for some time afterwards.

1.6 P.M. Muscle was found to be infinitely sensitive. Nerve, stimulated with 0.06 volt, produced distinct contraction ; both sides give the same result.

This experiment shows how sensitive muscle and nerve remain for some time after death from purely mechanical causes.

Experiment VIII. The right thigh of a frog (Rana tiqrina) was ligatured so as to completely prevent the blood circulating in the part below the ligature. The sciatic nerve was not