THE

THEORY AND PRACTICE

OF

MEDICINE.

INTRODUCTION.

General view of the subject. Natural divisions of diseases. Investigation of disease. History. Pathology. Treatment. Of General Pathology. Criticism on Dr. Cullen's Nosology. Division into acute and chronic diseases.

THE diseases of the human body being very numerous, it becomes highly important to make such an arrangement of them as may assist the memory, and if possible contribute to a clearer comprehension of their analogies and peculiarities. The first and most simple distinction among diseases is founded upon their susceptibility of relief from manual operation. This has led to the division of the science of medicine into the two great branches of Physic and Surgery, which, though for the most part taught and practised separately, are yet so intimately connected, that neither can be appreciated in all its bearings, unless viewed in conjunction with the other. Such a survey points out that the diseases of the external and internal parts of the body are all regulated by the same laws, judged of by the same means, excited frequently by the same causes, and alleviated or removed on the same general principles. Under this impression, it would be unnecessary for me to attempt to define with accuracy the boundaries of Physic and Surgery, which, for all useful purposes, is sufficiently effected by the courtesy of the world.

Among the diseases which fall under the particular cognizance of the Physician, the first distinction is into such as are attended, or unattended by Fever:-that is to say, into the febrile and apyrexial. The second is into the acute (by which physicians understand diseases running a short and defined course); and chronic, or such as are lingering and of uncertain duration. A third distinction, equally elementary, is into constitutional and local diseases;-into those, namely, in which the whole system equally partakes, and those which depend more obviously and immediately upon the læsion of some particular organ. These are not to be considered in any other light than as artificial boundaries; or as beacons which may direct the student while in the path of education, but which may and ought to be neglected when that object is attained. It will hereafter be shown, that acute and chronic, local and constitutional diseases, are blended together in an infinite variety of ways, which it is in vain to attempt to unravel by the most ingenious contrivances of an artificial system. It is, in fact, a most important principle in Pathology, that an intimate connection is established between all the parts of the living system, which must necessarily baffle every attempt to give a perfect idea of diseases by separate investigations. With this understanding, however, thoroughly impressed upon the mind, such distinctions may safely and advantageously be made the ground-work of a nosological arrangement of diseases, well calculated to elucidate the first principles of the science; and they are taken as the basis of that which is observed in the following pages.

Mode of investigating a disease.-1. An inquiry into any particular disease includes in the first place a detail of the symptoms by which it is characterized in its several stages; and in particular of such as serve to distinguish it from other diseases with which it is in danger of being confounded; or to direct the judgment of the physician as to its probable duration and termination; and, lastly, of the appearances found after death. This first branch of the subject, therefore, includes diagnosis and prognosis, and whatever can be learned regarding a disease by clinical observation. It constitutes the history of the disease-the Medicina Prima of ancient authors. 2. The second object of inquiry is the pathology of the

complaint, by which is to be understood whatever can be made out concerning it by a process of reasoning. It includes an investigation of the predisposing and exciting causes (ætiology), and of the seat and nature of the disease, in as far as they can be ascertained. This is the most abstruse and difficult part of the inquiry; and though, even if successfully prosecuted, it does not always lead to practical results, yet in most instances it throws the surest light upon this object of research; and where it fails to point out the means of relief, often suggests the reason, why that is difficult, tedious, or impossible.

3. The third topic of inquiry in the account of a particular disease is the treatment. To this, of course, every other part of the subject must be considered as subordinate. As a general principle of the first importance, I would wish here to inculcate strongly upon the student, that the cure of all diseases must be effected by the powers of the living system; and that his remedies are merely to be employed with the view of placing the body under the most favourable circumstances for resisting disease. The general principles upon which the treatment of any disorder is to be conducted can alone find a place in this work. A knowledge of the manner of adapting these to the infinitely varied circumstances under which disease occurs, must be the result of personal experience, as it will be the sure reward of diligent observation.

In an elementary work on the Theory and Practice of Physic, something more, however, is required than a mere detail of the individual diseases to which the human body is subject. They have their points of analogy as well as of dissimilarity; and it is an object of consequence to determine these analogies, to show the great features of resemblance which all diseases bear, and to trace the almost insensible gradations by which they run into each other, and which enable us, either to view them as separate objects of inquiry, or as the closely connected members of a great family. This beautiful mixture of uniformity and variety in the phenomena of disease presents one of the most formidable obstacles which a work of this nature has to encounter, and it can only be surmounted, and that partially, by occasional digressions into the obscure doctrines of GENERAL PATHO LOGY. Upon these the science of Medicine may be said

strictly to be founded. They will, of course, be more or less important, and applicable to practice, in proportion as they are supported by views more or less correct of Chemistry and Mechanics, and of those laws which regulate the vital actions of the animal œconomy. The obscurity which is acknowledged to pervade all parts of general pathology, is, in some, only faintly broken in upon by the glimmerings of conjecture. These will in the present volume be simply noticed, without attempting to estimate, with any degree of nicety, their claims to our confidence.

The work is divided into two parts, of which the first treats of acute, and the second of chronic disorders. The arrangement of diseases follows in its general outline, and in many of its details, the NOSOLOGY of Dr. Cullen; a work of great value, to which I shall have frequent occasion to refer, and to whose various merits I shall find many opportunities of doing justice. The alterations in it which I have adopted are such as appear to be rendered necessary, from the improvements which have taken place in pathology since his time. The great features, however, of Dr. Cullen's system are retained, which being founded on a close observation of the phenomena of disease, will probably continue for ever to be the surest basis of any elementary view of THE THEORY AND PRACTICE OF MEDICINE.