It is not a little interesting to note that the period to which we have referred, 1910 to 1915, in which the mortality of tuberculosis has fallen so steadily while that of cancer has so steadily risen, even in greater proportion, is that in which active laboratory work has also dazzled the public and professional mind. The enormous activity with the microscope in regard to the minute structure of the diseased tissues, and the elaborate and extensive work done in animal experimentation, have turned the thoughts of many from the homely and practical studies of the human frame in its various departures from health; thus too little attention has been given to the deranged activities of its various organs, and the perverted metabolism which, has resulted from the stress and strain, with the temptations and errors accompanying the present intensity of human civilization. Matters being as they are it is hardly to be expected that the surgeons would incline to any other treatment than by the knife, especially since good pathologists have asserted that cancer is only a local affair and have urged its early removal. Nor would one expect that the surgeon would think along medical lines and investigate metabolic conditions, when the immediate results of operation seemed often to be so satisfactory. Neither would one expect the surgeon to seek from statistics the unfavorable aspects of this line of treatment, but rather those from which he could draw encouragement in trying to overcome so dire a disease. But slowly light is beginning to shine, and you have seen and heard enough to realize that the simple removal of the _product_ of the cancerous process, and surrounding tissues, can never check greatly the morbidity and mortality of cancer. You know now what the real cancer problem is. It surely is not the sole continuance of a line of treatment under which the death rate has steadily risen from 63 to 81.1 persons in each 100,000 living, or 28.7 per cent since 1900, with a mortality of about 90 per cent of those once affected with the disease. The cancer problem is by no means yet solved, but I think that you will all agree with me that we are on the right track, and I cannot do better than to close with a remark I made to you two years ago: “Scientific research must still go on in the laboratory; but clinical research and study, with laboratory work, on the human subject, which have not been hitherto sufficiently cultivated, should be pushed, so that by a mass of carefully recorded observations the truth or falsity of what has been here quoted and said may be refuted or confirmed.” LECTURE V DIETETIC AND MEDICAL TREATMENT OF CANCER PROPHYLAXIS