This propensity has shown itself in some measure even among physicians. Enthusiasts in our profession have always been disposed to attribute to favorite remedies, a sort of universality in their operation upon disease. Every new medicine that comes up to notice has almost every kind of virtue ascribed to it by such physicians. And it is only by long-continued and well-weighed experience, that the statements made in relation to any remedy can be sifted, and the real truth be discovered in regard to the degree and extent of its efficacy, and the circumstances which should govern us in its use. This process has been gone through with, in the case of every article of the materia medica that has ever had any notoriety. Take for example, digitalis. At one time, this medicine was in common use in many diseases, and especially in consumption; and some enthusiasts, if they did not go so far as to say that it was a certain cure when used sufficiently early, at least extolled it as almost a specific for this disease. The accumulated and compared experience of physicians in regard to it has at length determined pretty nearly its value, and while it is now used far less than it once was, it is used more judiciously from the more definite knowledge of its effects which this experience has gained for us. The same remarks could be made about other articles.[6] And while the test of experience has corrected our valuation of some remedies, and thus enabled us to use them with more skill; there are others once supposed to be valuable, which, under the application of this test, have gone wholly out of use. I will mention but a single example. Dr. Beddoes, an English physician of some note, but a great enthusiast, thought that some of the gases might be advantageously used in the treatment of disease. The results were said to be astonishing, and the practice of pneumatic medicine, as it was called, became very prevalent. I find in a work, called Medical Extracts, published in 1799, the narrative of sixty-nine cases of various diseases, said to be cured by the respiring of these gases. Among them are certainly some formidable maladies, such as dropsy in the head and chest, consumption, gout, epilepsy, leprosy, scrofula, &c. Some of these cases had been previously under the care of celebrated physicians, and some had even been pronounced by them to be incurable. A description given by one of the patients, a clergyman, of his own case, almost transcends the descriptions given now-a-days by some clergymen of the effects of some patent medicine, or of the infinitesimal doses of homœopathy. Now, if the respiring of these gases really did produce these results, or any good proportion of them, the same practice would have been in vogue now. But it has not stood the test of experience, and therefore has been rejected. No physician at the present day thinks of setting his patients to breathing these gases.