Professor Galvani's frog rest upon a sure foundation of fact. Signora Galvani--so runs one version of the story--lay sick upon a couch in a room in which there was that chaos of domestic utensils and philosophical apparatus that may still be observed sometimes in the abodes of men addicted to science. The Professor himself had prepared the frogs for the stew-pan, and left them upon a table near the conductor of an electrical machine. A student, while experimenting with the machine, chanced to touch with a steel instrument one of the frogs at the intersection of the legs. The sick lady observed that, as often as he did so, the legs were convulsed, or, as we now say, were _galvanized_. Upon her husband's return to the room, she mentioned this strange thing to him, and he immediately repeated the experiment. From 1760 to 1790, as the reader is probably aware, all the scientific world was on the _qui vive_ with regard to electricity. The most brilliant reputations of that century had been won by electric discoveries. Franklin was still alive, to reward with his benignant approval those who should contribute anything valuable after his own immense additions to man's knowledge of this alluring and baffling element. It was, therefore, as much the spirit of the time as the genius of the man, that made Galvani seize this new fact with eagerness, and investigate it with untiring enthusiasm. It was a sad day for the frogs of the Pope's dominions when Signora Galvani observed those two naked legs fly apart and crook themselves with so much animation. There was slaughter in the swamps of Bologna for many a month thereafter. For mankind, however, it was a day to be held in everlasting remembrance, since it was then that was taken the first step toward the galvanic battery!