It is almost needless to say, these experiments upon the frog were not accomplished in a few days or a few weeks. Galvani had his duties as Professor of Anatomy to attend to, besides the obligations imposed upon him as a busy practitioner of medicine and surgery. At that time it was not nearly so much the custom as it is at present, to use frogs for experiments, with the idea that conclusions might be obtained of value for the biological sciences generally, and especially for medicine. There has always been an undercurrent of feeling that such experiments are more or less a beating of the air. Galvani found opposition not only to his views with regard to animal electricity as enunciated after experimental demonstration, but also met with no little ridicule because of the supposed waste of time at occupations that could not be expected to lead to any practical results. It was the custom among scientific men to laugh somewhat scornfully at his patient persistence in studying out every detail of electrical action on the frog, and one of the supposedly prominent scientists of the time even dubbed him the frog dancing master. This did not, however, deter Galvani from his work, though some of the bitter things must have proved cutting enough, and might have discouraged a smaller man, less confident of the scientific value of the work that he was doing. There were even phases of physical science quite apart from physiology or animal electricity, which he was able to illustrate by his experiments. He called special attention, for instance, to the fact that the lightning does not excite a single contraction of the muscle as is the case with a spark of artificial electricity, but that there are a series of muscular contractions succeeding one another rapidly in diminishing {123} energy and somewhat corresponding to the reiterated reports of thunder. This was Galvani's expression for the dying away of the electrical influence upon the muscle. He had thus evidently reached a hint of the pendulum-like swing with which electrical equilibrium is restored after its violent disturbance immediately following the lightning stroke. He noted, moreover, that for the production of muscular contractions the absolute appearance of lightning was not indispensable. Muscular twitchings were noted whenever the heavens were overclouded by a storm, or whenever clouds charged with electricity were passed above the conductor.