Primarily, the aim of the autopsy is to ascertain the cause of death and to acquire knowledge of the changes produced in the tissues and organs by the disease-process. If for no other purpose than that of extending our knowledge of disease, the autopsy becomes the most valuable factor in furthering the development of medical science. We have but entered into the broad, rich fields of pathology; at any time new facts may be discovered or observations of the most far-reaching nature made. From year to year the statistics of the most common diseases must be revised in the light of new conceptions of disease. Through the autopsy there lies within the reach of every practitioner the opportunity of contributing something worth while to the general sum of medical knowledge. There is not a pathologic condition in the medical category that does not call out for illumination upon some point or other. The phenomena of malignant tumors, the earliest stages of the so-called chronic affections, as well as the majority of the infectious diseases, require further autopsy observations for their elucidation. The autopsy establishment of the diagnosis is also of the greatest importance in giving value to vital statistics. Until we have a more universal confirmation of the clinical diagnosis by the pathologic our vital statistics must of necessity be imperfect. To the practitioner the autopsy offers further a most valuable control of subjectivity and a guide to methods of diagnosis and treatment. Without such a control no one is so likely to get into a dangerous rut as the practicing physician. The disclosures of the autopsy will enable him to correct faulty methods, and should effectually check any tendency to superficial diagnosis. Particularly is this the case with regard to such diagnostic methods as palpation, percussion and auscultation. Postmortem percussion offers a most valuable means of acquiring precision in this important branch of physical diagnosis. The percussion boundaries may be marked upon the body by pencil, or long pins may be inserted, so that when the body is opened the exact relation of the percussion area to the organ in question may be noted. In the case of palpable tumors the results of palpation before the body is opened should be carefully controlled by the findings when the actual conditions are exposed. Even when the cause of death seems obvious it is worth while to perform an autopsy at every opportunity offered, both for the sake of controlling technical methods and for the pictures of disease revealed. More accurate knowledge of the nature of the processes of disease can be obtained through one autopsy than through months of textbook reading. To the surgeon the opportunity of examining cases dying after surgical operation should be a source of great satisfaction. The review of anatomic relationships offered by the autopsy is in itself worth while, and in the case of healthy individuals killed