It may be safely said that no disease which has afflicted mankind has received as much attention as Cancer, or concerning which there has been as much diligent search to find out its nature and cause. Tuberculosis, which seemed at one time to threaten even the existence of the race, has sunk into relative significance, as we have learned its true nature and conquered some of the causes of its ravages, and reduced its mortality very largely. Syphilis, under various names, forms, and aspects, was formerly much more of a menace than now, and in earlier years caused veritable epidemics, but is now well understood and controlled. Leprosy is less of a terror than in earlier times, since it has been definitely shown not to be contagious. Smallpox no longer rages, and yellow fever, and the plague, and hook worm disease have been hunted down by scientific study and the application of proper sanitary and medical measures. And so on in regard to many of the ills which afflict mankind. But cancer has held its own and has even increased in frequency, with rapid strides and bounds in some localities, until now it looms large as a national[1] or even universal scourge; it has been estimated to cause the death of half a million persons yearly among the civilized people of the earth, and untold misery and suffering to many times this number. And all this is still going on in spite of the earnest, faithful, and intelligent labors of innumerable research workers, the sacrifice of countless animal lives, and the expenditure of vast sums of money; and the end, as far as relates to its prevention and cure, seems almost as far away as ever, for many surgeons, in past and present times, have acknowledged their inability to cope with the disease. Much, however, has already been established by scientific research, and still more earnest thought, observation, and endeavor should be given to seeking most diligently for the cause of the disease, in the laboratory as well as in practice; for there must be some cause of cancer, and also some reason for its steady increase. But it is never to be forgotten that, as Pope says, “the proper study of mankind is man,” and clinical observation, with laboratory research, on cancer as it appears in the human being, must be the ultimate base upon which all true advance in the knowledge of the nature, treatment, and prevention of the malady can ever rest. To effect this we must study the human being in all relations of life, must know the constitution and class of subjects in which the disease is most apt to manifest itself, understand the chemico-physiologic actions going on in the system, before and during the existence of the disease, and by a process of synthesis and deduction understand what is wrong and endeavor to correct it.