In exposing the errors and faults of the medical profession and of the public, while I have unflinchingly aimed at the truth I have endeavored to avoid a censorious spirit, and to give to human frailty all the tolerance that can properly be demanded. I trust the reader will therefore find, that, in the language of my motto, “there are no wasps, there are no hornets here.” That I have escaped all error myself I do not claim. Some points may be too strongly stated, and some provisionary and modifying considerations may be omitted. I ask of the reader a reasonable indulgence, but none which shall be inconsistent with an honest and candid criticism. In the practice of medicine there are some points upon which there should be a common understanding between the physician and the friends and attendants of the sick. From the want of such an understanding the purposes and plans of the practitioner are often interfered with, and sometimes are effectually thwarted. A considerable portion therefore of this work is devoted to an elucidation of the points referred to. In the chapter on the uncertainty of medicine, and in other places, also, I point out the difficulties which are encountered in the study and practice of medicine. These difficulties demand of the physician the exercise of higher and more cultivated powers, than are needed for the successful prosecution of most other studies and pursuits. I therefore make it a principal object to urge, by every consideration, the importance of a well-educated medical profession. Every man has a personal interest in maintaining the barriers by which the organizations of the profession undertake to protect the community from the evils, which they would suffer from ignorance and imposture, if these barriers were destroyed. It is especially for the advantage of the _people_, and not, as is commonly supposed, of physicians, that there should be a proper standard of medical education. My first chapter, on the uncertainty of medicine, may perhaps be considered by some as too strictly professional for the common reader. I ask for it, however, a careful perusal. I have endeavored to strip the subject of all technicalities, and a full understanding of the views there presented is necessary to a proper appreciation of the considerations contained in some of the succeeding chapters. I write in part for the profession, and in part for the community at large. I ask both to look candidly at the views which I present of their ‘_mutual duties, relations, and interests_.’ A reform is needed in the opinions and practices both of physicians, and of the people, in regard to medical subjects. This reform is fairly begun in the profession, and there may be seen, even amid all the present diversified and flaunting displays of quackery, some indications of its commencement in the community. The volume which I now offer to the public is a humble effort to promote this reform. W. HOOKER. _Norwich, Conn., June, 1849._