In reference to the action of medicines and external agents on the animal body, we would observe, that warmth and moisture always expand it, and bayberry bark, tannin, and gum catechu always contract it; and that these agents have these effects at all times (provided, however, there be sufficient vitality in the part to manifest these peculiar changes) and under all circumstances. If a blister be applied to the external surface of an animal, and it produces irritation, it always has a tendency to produce that effect, whatever part of the living organism it may be applied to. So alcohol always has a tendency to stimulate; whether given by the mouth, or rubbed on the external surface, it will produce an excitement of nerves, heart, and arteries, and of course the muscles partake of the influence. Again, marshmallows, gum acacia, slippery elm, &c., always lubricate the mucous surfaces, quiet irritation, and relieve inflammatory symptoms. It follows, of course, 1st. That when any other effects than those just named are seen to follow the administration of these articles, they must be attributed to the morbid state of the parts to which they are applied; 2d. That a medicine which is good to promote a given effect in one form of disease, will be equally good for the same purpose in another form of disease in the same tissue. Thus, if an infusion of mallows is good for inflammation of the stomach, and will lubricate the surface, and allay irritation in that organ, then it is equally good for the same purpose in inflammation of the bowels and bladder. What we wish the reader to understand is this: that a medicine used for any particular symptom in one form of disease, if it be a sanative agent, is equally good for the same symptom in every form. Medical men range their various remedies under different heads. Thus opium is called narcotic, aloes purgative or cathartic, potass diuretic, &c. And because the same results do not always follow the administration of these articles, they are perplexed, and are compelled to try every new remedy, in hopes to find a specific; not knowing that many of their _"best medicines"_ (opium, for example) war against the vital principle, and as soon as they get into the system, nature sets up a strong action to counteract their effects; in short, to get them out of the system in the quickest possible manner: sometimes they pass through the kidneys; at other times, the intestinal canal, the lungs, or surface, afford them egress. And because a certain agent does not always act in their hands with unerring certainty, they seem to suppose that the same uncertainty attends the administration of every article in the _materia medica_. The medicines we recommend owe their diuretic, astringent, diaphoretic, and cathartic powers to their aromatic, relaxing, antispasmodic, lubricating, and irritating properties; and if we give them with a view of producing a certain result, and they do not act just as we wish, it