A great change has taken place in the remedies which are now in common use in Philadelphia. I shall briefly mention such of them as are new, and then take notice of the new and different modes of exhibiting such as were in use between the years 1760 and 1766. Vaccination has been generally adopted in our city, in preference to inoculation with variolous matter. Digitalis, lead, zinc, and arsenic are now common remedies in the hands of most of our practitioners. Cold air, cold water, and ice are among the new remedies of modern practice in Philadelphia. Blood-letting is now used in nearly all diseases of violent excitement, not only in the blood-vessels, but in other parts of the body. Its use is not, as in former times, limited to ounces in specific diseases, but regulated by their force, and the importance of the parts affected to health and life; nor is it forbidden, as formerly, in infancy, in extreme old age, in the summer months, nor in the period of menstruation, where symptoms of a violent, or of a suffocated disease, manifested by an active or a feeble pulse, indicate it to be necessary. Leeches are now in general use in diseases which are removed, by their seat or local nature, beyond the influence of the lancet. For the introduction of this excellent remedy into our city we are indebted to Mr. John Cunitz. Opium and bark, which were formerly given in disguise, or with a trembling hand, are now, not only prescribed by physicians, but often purchased, and taken without their advice, by many of the citizens of Philadelphia. They even occupy a shelf in the closets of many families. The use of mercury has been revived, and a salivation has been extended; with great improvements and success, to nearly all violent and obstinate diseases. Nor has the influence of reason over ignorance and prejudice, with respect to that noble medicine, stopped here. Cold water, once supposed to be incompatible with its use, is now applied to the body, in malignant fevers, in order to insure and accelerate its operation upon the salivary glands. Wine is given in large quantities, when indicated, without the least fear of producing intoxication. The warm and cold baths, which were formerly confined chiefly to patients in the Pennsylvania hospital, are now common prescriptions in private practice. Exercise, country air, and the sea shore, are now universally recommended in chronic diseases, and in the debility which precedes and follows them. Great pains are now taken to regulate the quantity and quality of aliments and drinks, by the peculiar state of the system. Let us now inquire into the influence of the new opinions in medicine, and the new remedies which have been mentioned, upon human life.