SECTION C-PATHOLOGY

(Hall 13, September 22, 10 a. m.)

CHAIRMAN: PROFESSOR SIMON FLEXNER, Director of the Rockefeller Institute. SPEAKERS: PROFESSOR LUDVIG HEKTOEN, University of Chicago.

PROFESSOR JOHANNES ORTH, University of Berlin.

PROFESSOR SHIBASABURO KITASTO, University of Tokio. SECRETARY: DR. W. MCN. MILLER, University of Missouri.

THE RELATIONS OF PATHOLOGY

BY LUDVIG HEKTOEN

[Ludvig Hektoen, Professor and Head of Department of Pathology and Bacteriology, University of Chicago, Director of Memorial Institute for Infectious Diseases. b. July 2, 1863, Wisconsin. A.B. Luther College, 1883; A.M. 1902; M.D. College of Physicians and Surgeons, Chicago, 1887; Post-graduate, Upsala, Berlin, and Prague. Pathologist, Cook County Hospital, Chicago, 1890-1904; Physician to Coroner's Office, Cook County, 1890-94. Co-editor, Journal of Infectious Diseases, etc.]

OSTWALD, the inspiring interpreter of the great principles of science, states that "We have just passed through a period in which all sciences have been isolated, a period of specialization, and we find ourselves in an epoch in which the synthetic factors in science are gaining a constantly increasing significance. . . Everywhere the individual sciences seek points of contact with one another; everywhere the investigator determines the value which his special results may have in the solving of the general problems. In short, all sciences are tending to be philosophical. Now here is this tendency toward fundamental explanation so great as in biology."

Pathology a Division of Biology

Disease is the common lot of all forms of life, high as well as low, animal as well as vegetable, and it is the special province of pathology, the science of disease, to study life in its abnormal forms and activities. Hence pathology is a division of biology, and it is in fact pathological biology, but its relationships as such have not always been so clearly appreciated as they ought to be; in part this may be explained on account of the very special stress placed on its direct application to practical medicine in the service of the art of healing. For this and other reasons pathology in many respects has remained somewhat isolated among biological sciences. The early pathologists took the almost exclusive standpoint of

human medicine and for a long time the vast resources of general biology remained practically unused in the study of disease. On the other hand, owing to lack of appreciation of the fact that disease is a phenomenon of life, in other words, owing to the unnatural separation of the biologic study of disease from general biology, the subject of disease has rather repelled the average student of biology, who therefore seems to have neglected to utilize fully the approaches offered by pathology to a better knowledge of the phenomena of life.

In view of the extent to which man has busied himself with the study of all forms of animal life in all accessible parts of the world, is it not rather strange and an evidence of lack of coördination that the occurrence of cancer throughout the whole vertebrate kingdom should have been made out definitely only during the last year? Yet this demonstration by the Cancer Research Fund in London, and the further demonstration that cancer has the same fundamental characters as in man when it occurs in fish, reptile, and bird, renders it extremely improbable that either climate or diet of man has anything to do with the direct causation of cancer, thus putting an end to much needless speculation and materially narrowing the scope of a most important inquiry.

Pathological Processes in Evolution

In some quarters disease has been regarded merely as an expression of inferiority and weakness, and as part at least of the means by which inexorable nature carries out the verdict of extermination. Parasitism for instance has been designated as a weapon to eliminate those who fall below a certain standard. Consideration of the nature of disease from this point of view gives to disease merely a negative evolutional significance, as it would cause no new and better qualities in the descendency. Closer examination would tend to show, however, that processes of disease may have a different significance of a more positive nature in evolution. There are numerous simple as well as complex physiological processes which, when set in motion by abnormal conditions, appear to be of advantage not only to the individual but also to the species. As examples of adaptive processes at first sight of more special individual advantage may be mentioned regeneration, hypertrophy, the interesting adaptations to new and strange conditions of which bones and vessels are capable, certain phases of thrombosis, and even atrophy, which has been described as the faculty of an organ to adapt itself to conditions of diminished nutrition, thus circumventing necrosis, a faculty of great advantage when the period of diminished food-supply is only temporary. No one

can fail to see much that must be useful and advantageous in the complex reactions to injuries observed in inflammations, the significance of which has been greatly broadened through the wellknown comparative study of Metchnikoff. In the case of immunity, natural and acquired, our wonder knows no bounds, so marvelous are the precision and scope of the protective reactions, concerning which so much has been brought to light in recent years and which lend themselves well to comparative studies. In the case of degenerations and tumors it is not possible to recognize any direct or indirect advantage, and certainly no one has yet been able to see malignant tumors in such favorable light. In these instances. first mentioned the pathologic reactions have physiologic prototypes; they are adaptations of physiologic processes. Regeneration and growth are taking place constantly in health. Phagocytosis, on which so much stress has been laid in inflammation, is merely an exaggeration of normal nutritive processes in certain cells. At present the production of antitoxins and other anti-bodies is best explained as the result of special adaptations of normal stereo-chemical mechanisms whereby nutrition is carried on. A very noticeable difference between the physiologic and pathologic manifestations of these functions is seen in their imperfections and shortcomings under many of the abnormal conditions. Incomplete regeneration resulting in the formation of scars often has many disadvantages. Inflammations frequently establish conditions in themselves fraught with dangers. The reactions of immunity may not neutralize quickly enough the toxins nor destroy promptly enough the invading organisms. Hence there is abundant scope for the intervention of the physician armed with all the various appliances of his art, some of the most useful of which are the products of artificially produced biologic reactions. But after all the individual organisms must enjoy the best chances for survival and reproduction that suffer least harm because best able to adapt themselves and to protect the life and function of their cells under conditions of disease.

Just as there are variations in the limits of physiologic regulatory mechanisms, so also there are individual differences of degree in the power of adaptive and protective reactions to establish themselves in disease and permit continuance of life. In progressive evolution it naturally must be in the descendants of individuals with the best adaptive and protective powers that an increasing completeness and perfection of such powers will be found. Viewed in this light many processes of disease assume a significance of positive character in biologic evolution, a point of view that would increase the interest in pathology among biologists in general, and thus tend to further its development along broader lines and

lead to coördination of knowledge and broad and still broader generalizations as to causes, nature, and processes of disease. At present we may be said to be gathering materials for this broader comparative pathological biology of the future in the same way as the older naturalists gathered materials for the biologist of the present day.

Pathology and Research

At least in certain fields the student of the pure science of disease is primarily interested in the knowledge of disease for its own sake without much thought or immediate care as to any prompt practical use to which such contributions as he may make to this knowledge may be put. It is true here as it is in general that most things are done only on account of the results expected from them in the future, but immediate technical utility is not always the sole guiding principle of the investigator in pathologic domains. The history of pathology shows him that in this science as well as in its synthetic sciences all actual increase in knowledge eventually helps to relieve suffering. Everywhere the most intimate relations may be seen between the progress of medical knowledge and the progress of medical art. Like other sciences pathology furnishes many examples of the rather unexpected importance and the even profound influence of the new observation, the new methods of study, the new point of view that at first seemed to have but limited significance. Indeed some of the fundamental ideas of scientific medicine have arisen in this way. It has been well said that no knowledge of substance or force or life is so remote or minute, but that to-morrow it may become an indispensable need (van Hise). We in America have therefore much reason to rejoice because of the strong movement that is starting in the interest of scholarship and of research in pathology, a movement that of course does not limit its influence merely to the advancement of knowledge, but exercises as well a powerful influence upon the diffusion of knowledge. The man who is so full of enthusiasm for pathology that he will "burn his lamp for its advancement" is likely also to be an inspiring teacher illuminating the older knowledge with the discovery of to-day and placing the new facts in their proper relations to what is already known and to what will be known. Medicine in this country has been so preoccupied with building-up medical education for the training of physicians that comparatively little energy has been available for the upbuilding of medical science itself. Thus pathology in the universities has not been taught until very recently in such a way that graduate students might take it up as a branch to be followed through long stretches of labor. This is regrettable, but in some of our universities pathology is now placed on equal footing with other natural sciences and fully recognized as