Former experiments having shown that when the functions of the brain are destroyed the secretory organs invariably ceased to perform their office, and consequently that the various secretions were probably dependent on nervous influence, it appeared desirable to ascertain this point by dividing the nervous branches by which some one gland is supplied, and observing the effect. But on account of the difficulty of the operation itself, and of the injury done to adjacent parts, it appears extremely difficult to determine the real influence of the nerves in the natural state of all the functions. There are, however, some experiments on the preternatural secretion excited by the action of arsenic, and its interruption by division of the nerves, which the author thinks may deserve to be recorded as tending to elucidate so important a subject. Mr. Brodie had formerly observed in dogs poisoned by arsenic, a very copious secretion of mucus and watery fluid from the coats of the stomach and intestines, and so rapidly excited, that he conceived this to be a favourable instance for observing the effect of dividing those nerves which supply the stomach.