We should naturally look to physicians for an answer to such a question; but the great lights of the profession--men of the rank of Astley Cooper, Brodie, Abernethy, Holmes--all assure the public, that no man of them knows, and no man has ever known, how medicinal substances work in the system, and why they produce the effects they do. Even of a substance so common as Peruvian bark, no one knows why and how it acts as a tonic; nor is there any certainty of its being a benefit to mankind. There is no science of medicine. The "Red Lane" of the children leads to a region which is still mysterious and unknown; for when the eye can explore its recesses, a change has occurred in it, which is also mysterious and unknown: it is dead. Quacks tell us, in every newspaper, that they can cure and prevent disease by pouring or dropping something down our throats, and we have heard this so often, that, when a man is sick, the first thing that occurs to him is to "take physic." But physicians who are honest, intelligent, and in an independent position, appear to be coming over to the opinion that this is generally a delusion. We see eminent physicians prescribing for the most malignant fevers little but open windows, plenty of blankets, Nightingale nursing, and beef tea. Many young physicians, too, have gladly availed themselves of the ingenuity of Hahnemann, and satisfy at once their consciences and their patients by prescribing doses of medicine that are next to no medicine at all. The higher we go among the doctors, the more sweeping and emphatic is the assurance we receive that the profession does not understand the operation of medicines in the living body, and does not really approve their employment. If something more is known of the operation of alcohol than of any other chemical fluid,--if there is any approach to certainty respecting it,--we owe it chiefly to the teetotalers, because it is they who have provoked contradiction, excited inquiry, and suggested experiment. They have not done much themselves in the way of investigation, but they started the topic, and have kept it alive. They have also published a few pages which throw light upon the points in dispute. After going over the ground pretty thoroughly, I can tell the reader in a few words the substance of what has been ascertained, and plausibly inferred, concerning the effects of wine, beer, and spirits upon the human constitution.