The same operations were performed upon a large female frog full of spawn. Four hours afterwards, she was observed covered by a male, who had been treated in a similar manner. I mention this circumstance, as it tends to prove that the pain occasioned by the operation was probably not so great as to produce much fallacy. On the day following, she had spawned, and on the sixth day from the operations, she was strangled. When laid upon a plate of zinc, and excited by means of a rod of silver, the contractions were found extremely feeble in the leg whose artery had been tied, and ceased altogether in about twenty-two hours after her death. In the leg, whose nerve had been divided, they appeared as vigorous as they usually are in legs to which no injury has been previously done, and continued excitable upwards of two days after they had ceased to be so in the other. EXPERIMENT III. Having tied the crural artery on one side, and divided the sciatic nerve on the other, on three full grown male frogs, I strangled them all on the sixth day following. My motive for killing the frogs, subjected to such experiments, either in this manner or by crushing their heads, will be obvious. It was of consequence to preserve their circulation as entire as possible, and, at the same time, avoid the continuance of pain, which by exhausting all the parts of the body, whose communication with the brain was not interrupted, might considerably have affected the result of the experiments. The contractions excited by means of the metals, were, in all these instances, likewise as much more strong and durable in the legs, whose nerves had been divided, than what they were in the legs, whose arteries had been tied, as what I had found them to be in the preceding experiment. Having thus found, that a diminution of the circulation of a part, was accompanied with a proportionable diminution of the respective powers of nerves and muscles in that part, I next proceeded to examine if an increased circulation would be attended with a proportionable increase of these powers. That this is actually the case, with respect to the nerves, the few facts which I have related of the eye, in a state of inflammation, have a tendency to prove; and we all know how much the sensibility of every part of the body is increased, by an increase of vascular action. That a similar relation subsists between an increased action of the arteries, and the contractile power of muscles, is, I think, proved by the following experiment. _Experiments made with a view of ascertaining some of the Effects of Inflammation._ EXPERIMENT I.