1. We have already seen that with utter medical neglect the death rate of cancer has steadily and greatly increased in the United States, of late years, in spite of the prodigious advances of surgery during the same time. This is also true in all the countries from which we have any accurate statistics. We know also that tuberculosis, as a result of careful medical attention, has decreased in mortality by almost as great a percentage as cancer has increased. The same is reported by reliable observers all over the civilized world. 2. Any number of observers, in many lands, have recorded the almost entire absence of cancer among aborigines, living simple lives, largely vegetarian; they have also shown the definite increase in the disease, and in its mortality, in proportion to their adoption of the customs and diet of so-called modern civilization. 3. This increase of cancer mortality seems to depend largely upon the altered conditions of life attending advanced civilization, particularly along the lines of self-indulgence in eating and drinking and in indolence. 4. Statistics from many countries show that increase in the consumption of meat, coffee, and alcoholic beverages, appears to be coincident with a very great and proportionately greater augmentation of the mortality from cancer. 5. Clinical observation has time and again shown the effect of specific nerve strain and shock in the development of cancer; and there seems to be little question but that the enormous nerve strain of modern life is an element of importance in this direction, both through metabolic disturbance and by direct action on living cells. 6. At present no clear demonstration is possible of the direct method by which errors of metabolism effect the changes in cells to which we give the name malignant, any more than we know how other alterations on the body are produced; such as arterial degeneration, bone changes, obesity, etc., which are recognized as due to metabolic derangement. 7. The results which have been observed in connection with the starvation of cancer, by ligature of vessels, illustrate the relation of the blood supply to growing cancer. 8. Finally, the repeated observation and report of the spontaneous disappearance of cancer, by careful and competent medical men, shows that conditions of the system may arise which are antagonistic to malignant growth, even when it has begun to take place; just as there are other conditions of the system which favor the aberrant action of previously normal cells, resulting in cancer.