representation of the whole arrangement. Everytime this circuit was closed, the frog was stronglyconvulsed; but no commotion occurred by simplytouching the muscles of the calf with the spine ofthe frog, when the outer hands of the operators werenot united.

These highly interesting experiments can berepeated under those circumstances only in which thelarger animals employed can be had as soon as killed.Aldini had many opportunities of experimenting onthe bodies of decapitated criminals, and made severalsuccessful inquiries of this kind, by employing thehuman body in the same manner as the trunk of thecalf in the last described experiment.

The same sagacious physiologist made severalother experiments in animal electricity, which can beeasily repeated by any one wdio can command a frogof strong vital power. The frog is to be prepared inthe usual way, and, after moistening it in salt water,the operator takes hold of the legs, and brings thecrural nerves to his own tongue. The Galvaniccircuit, in this case, is through the frog and theoperator, from the hand to the tongue. The usualcommotions are produced at every contact betweenthe nerves and the tongue.

If several persons form a chain amongst them-selves by joining hands, w r ell moistened in salt water,and that the person at one of the extremities of thechain hold the legs of a prepared frog, contractionsare produced whenever the circuit is closed by thedisengaged hand, at the other end of the chain, andthe crural nerves of the frog. Many persons havefailed in repeating these experiments, from their notoperating on large frogs of great activity ; and othersby not attending strictly to the necessary preparations.

The experimental illustrations hitherto broughtforward in these lectures, would, of themselves, besufficient evidence to convince most physiologicalenquirers, who have no preconceived notions to sup-port, that in the animal frame the different organismse 2