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every contact that is made between the water and thewire. If I permit the wire to remain immersed, andoccasionally open and close the circuit by alternatelylifting and dipping the frog from, and into, the water,the phenomena produced are precisely the same bythis process as by the other.

The experiment is pleasingly and instructivelyvaried, by having a circuit of several persons betweenthe limbs of the frog and the water in the vessel.Suppose, for instance, eight or ten persons joinhands, so as to form a chain from one end to theother. The disengaged hand of one of the extremi-ties of the chain, or range of persons, is to take holdof the legs of the frog, and the disengaged hand atthe other extremity of the range, is to be immersedin one portion of the water. This done, the pendentspine of the frog is to be occasionally dipped intothe other portion of water, which, in every case, willoccasion the usual convulsive commotions. In thiscase the conducting arc is the chain of personsforming the greatest portion of the circuit.

This experiment may be varied in different ways.For instance, the spine of the frog may be permittedto remain immersed in one portion of the water, andthe circuit may be closed and opened by the hand atthe other extremity of the arrangement. It mayalso be varied by keeping immersed both the frog atone end and the hand at the other end, the openingsand closings being accomplished by any two adjoin-ing hands in the arrangement. But the most singulareffect is produced by holding the spine in the hand,and permitting the pendent toes of the frog to justtouch the surface of the water, the remaining part ofthe circuit being previously completed. By tbissimple immersion of the limbs, the most singularantick motions are exhibited by them. The toes arethrown out of the water at the first contact, whichopens the circuit; they immediately fall down againand close it, at which moment they are again con-vulsed and thrown out, and again the circuit is