A system of practical medicine. By American authors. Vol. 1

by Unknown

Pathology can never be out of view in connection with either the theoretical or the practical study of diagnosis. But it is most closely regarded when the last of these questions is before us, since the names of diseases generally have a more or less distinct reference to their pathological nature. Yet clinical observation always suggests the early use of provisional terms for recognized groupings of morbid phenomena; and sometimes these clinical designations remain for a long time in use because of the imperfection of pathology.

We ascertain, in practice, the nature of a given case, first, by considering its symptoms. These are those obvious evidences of deviation from health which the patient himself is aware of, or which the physician readily discerns or elicits by simple inquiry or examination.

Secondly, taking the clue furnished by symptoms, a closer inspection is made, with the intent of finding what is the actual state of important organs, as the heart, lungs, liver, spleen, kidneys, and alimentary canal.

Lastly, when these means fail to remove all obscurity, or when special scientific investigation is practicable, instruments of precision are employed, as the thermometer, sphygmograph, ophthalmoscope, æsthesiometer, or aspirator; or by the microscope and chemical analyses still more minute examination is made into the particulars of the morbid processes present and their results.

We may subdivide diagnosis, then, into: 1, symptomatology; 2, organoscopy or physical diagnosis; 3, instrumental diagnosis.

Symptomatology.

Semeiology (from [Greek: sêmeion], a sign) is a term much in use, with essentially the same meaning as symptomatology, but less conveniently distinctive, since it does not so well indicate the contrast between obvious signs, or symptoms, and those more recondite, obtained by the methods of physical diagnosis.

Signs of disease cannot be recognized as such except by one who is familiar with the appearances, actions, and manifestations which belong to health. Nor can they be understood, so as to infer what they mean, without knowledge of normal physiology on the one hand, and, on the other, of the natural history of diseases. Physiology constitutes the etymological grammar, symptomatology the vocabulary, and diagnosis the syntax of practical medicine. Just as grammatical knowledge will not enable any one to read or speak a language without acquaintance with its words, so clinical observation is necessary to the physician over and above all the knowledge he may have of physiology and pathology. He must learn to know diseases by sight, or at least by personal contact and observation.

Every one has, of course, a general familiarity with the state and actions of his own and other bodies in health, yet a more exact knowledge of the movements of respiration, circulation, secretion, etc., as well as the form, size, and relative location of all the organs of the body, is needed. Physiology and medical anatomy furnish such information. The more thorough this knowledge is appropriated, the better fitted the student is for practical diagnosis. For its application, however, cultivation of all the perceptive powers is very important. Some men have a genius for quick and clear discernment of symptoms and for their interpretation, as well as for that of physical signs. But all can much improve their senses, and their sagacity in using them, by experience. For this, if for no other reason, scientific training, in field or laboratory studies, affords the best introduction to the work of the medical student and physician. The traits most needed for success in diagnosis are exactness and comprehensiveness. First, to be sure precisely what each sign is that comes under observation; next, to overlook no existing symptoms or physical signs; and, last, so to combine them into a mental map, diagram, or picture, as to make a coherent and rational whole. This nosogram may then be compared with the descriptions of standard authorities, to find its place (if it has one) in technical classification. First, however, ascertain the thing, the morbid state or combination of states; afterward the name, or morbid species, when practicable. It is always to be remembered that complication of diseases, or at least the existence of some irregular manifestations along with those which are characteristic, is more common than the occurrence of purely typical cases. The portraits of most diseases in the books are averages, like the composite class-photographs of Douglas Galton. Not nearly every case will correspond with such an average in all respects. Moreover, so great is the possible variety of alterations among the different organs of the body that the chances of two instances of disease being precisely alike in every particular are hardly greater than those in favor of every move being the same in two games of chess with the same opening.

In an essay like the present it is not easy to decide upon the best manner of treating the subject before us. Too much or too little may be said. With advanced readers the whole history of symptoms and physical signs might be left to the special discussions occurring in articles upon different diseases. But it may be taken for granted that those who consult the present work will do so either at a comparatively early stage of their studies or when time has made desirable a renewal of what may have been once known and then forgotten. Since, then, it is impossible to anticipate what may be the exact needs of either class, a somewhat elementary statement of main facts appears justifiable here.