Page:Encyclopædia Britannica, Ninth Edition, v. 15.djvu/827

Rh SYNOPTICAL VIEW.] MEDICINE 795 anatomy its form and structure. But, as a matter of fact, the structures and functions of the organism are not separable ; structure is correlated to function, whether active, dormant, or extinguished, and in like manner function is the twin notion of structure. In the ultimate analysis neither term means anything without the other, and both together mean life. It is owing mostly to its name that physiology is supposed to have a preponderant interest for the theory of disease ; the word anatomy is not well adapted to carry its own half of the structure- and-function dualism. Both in the historical development and in the logical connotation, anatomy is as much associated with the living and moving body as physiology itself ; but its etymology has always been against it, and it has become more and more difficult to retain for anatomy anything beyond the technicalities of the dissecting-room. The subject of general anatomy has for the most part dis appeared from modern text-books, its place being taken by histology, which deals with the minute structure of the simple tissues, and, in a wider acceptation, with the finer anatomy of all the organs and parts of the body. Histology, like anatomy, has had a somewhat technical or descriptive role assigned to it; and it is now mainly under physiology that the processes, activities, or living mechanisms of the body fall to be considered. The deve lopment of the body as a whole, and of its several tissues and organs, forms the subject of embryology ; many of the physiological types of diseased processes, especially the cellular, are discoverable in the embryological period. For the period of development, no arbitrary separation has been attempted hitherto between structure and function, and embryology is, in theory at least, as much physiolo gical as anatomical. The development of function is a legitimate and even desirable subject of scientific study, and a more distinctive place is probably awaiting it in the future; but so indissoluble does the union of structure and function present itself in the period of genesis and growth that the function has hardly as yet come to be abstracted from the structure, or the structure from tho function. The theory of disease rests, therefore, upon physiology, with its more or less technical adjuncts. Pathology is all that physiology is, with the engrossing and difficult element of perturbation, deflexion, or shortcoming added. By virtue of this element of deviation from the line of health, pathology is a discipline apart, with an abundant literature of its own, and with separate academical institutes and chairs. But pathology is also a discipline apart by virtue of concepts proper to itself. A great part of the theory of disease deals with changes or defects of structure and perturbations or failings of function, which may be intri cate or difficult to analyse, but are still well within sight of the line of health. Such are the common diseases of the organs and systems the inflammations, catarrhs, degenerations, hypertrophies, and functional derangements without lesion of the respiratory, circulatory, nervous, genitourinary, locomotor, and cutaneous systems. Con stitutional or general diseases belong also to the province of perturbations from the physiological course, such diseases as chlorosis, leukemia, diabetes, gout, rheumatism, scurvy, rickets, Addison s disease, exophthalmic goitre, and the febrile state. Again, congenital deficiencies or malformations, non-cancerous tumours, and the repairing of injuries exemplify no other laws than those of develop ment and growth. But with those examples the catalogue of physiological diseases is exhausted. We are left with a vast residue of diseases, which have always bulked largely in the popular mind, and have carried the most terrible associations with them. Such are the pestilences or diseases of peoples : the plague, sweating sickness, cholera, yellow fever, typhus fever, relapsing fever, typhoid fever, diphtheria, small-pox, measles, scarlet fever, influenza, dengue. Such also are the cancers, consumptions, leprosies, and other loathsome infections. This enormous residue is more than the half of disease, and the definition of disease or the scheme of pathology is brought to a test in finding room within its scientific categories for such maladies as those. The popular imagination in all countries has per sonified them ; medicine in its metaphysical period has regarded them as entities or things in themselves ; and it remains to be seen in what way or to what extent medicine in its scientific period will bring them within the category of perturbations of the physiological life. In considering, for a moment, where to place cancer in the pathological scheme, we shall arrive at a point of view from which the relation of the acute and chronic infections (or contagions) to diseases of the physiological order may be contemplated at least provisionally. Taking cancers, in a generic sense, to mean tumours that have acquired or are possessed of malignancy, we find that such tumours have many points in common with simple tumours, that they have grown out of the tissues of particular organs or parts under particular (functional) circumstances, and that they may, in general terms, be traced back to that point at which they left the line of health (see PATHOLOGY). The tracing back of tumours along the physiological track is often difficult and laborious; but there is no tumour of the body whose origins are not at length discoverable within the limits of physiological action. That which makes any tumour a cancer is something over and beyond ; it is a remarkable acquired property of reproducing its structure in manifold copies, or of infecting the organism of which it is itself a part. The tumour thus becomes a semi-independent power within the body ; it may be said, in a political figure, to have acquired autonomy, or to have become imperium in imperio. A due consideration of such a phenomenon as the infectiveness or cancerousness of some tumours will satisfy one that there are concepts in pathology which carry the investigator entirely beyoml physiological bounds or out of sight of the line of health, which bring him face to face with the notion of a disease as a thing in itself, and which thus constitute a peculiar subject-matter. There is nothing that we know among biological phenomena altogether analogous to the semi- independence which an integral part of the body, or con dition of the body, manifests towards the organism as a whole, and that, too, strictly in respect of its acquired devious or rebellious habit. The familiar definition of disease, morbus est vita prsder naturam, which embodies the notion of divergence from the line of health, makes no provision for an acquired autonomy of a morbid state ; and that definition has to be supplemented by another, which will recognize the possibility of a disease becoming a thing in itself. The old definition of Van Helmont, morbus est ens reale subsistens in corpore, appears to satisfy the require ment ; but that definition, although it grew out of the phenomena of disease as observed in fevers, was made too general, and has now associations that are too exclusively ontological and metaphysical. The supplementary definition should be as far as possible in the terms of the principal definition ; and we shall provide best in the pathological scheme for such a disease as cancer if, in addition to the formula morbus est vita prxter naturam, we construct a secondary formula, morbiis est vimim in vv&amp;lt;o. The notion of autonomy acquired by a morbid^ state implies, naturally, a pre-autonomous stage of the disease, which had been a mere perturbation of the norm of the body, capable of being measured by the physiological standard. The autonomous stage and the pre-autonomous