Part 5

24. CHARTS SHOWING THE TEMPERATURE CURVE IN TYPHO-MALARIAL FEVER: PART I., SHOWING PREDOMINANCE OF TYPHOIDAL ELEMENT; PART II., SHOWING PREDOMINANCE OF MALARIAL ELEMENT . . . . 617

GENERAL PATHOLOGY.

GENERAL MORBID PROCESSES.

GENERAL ETIOLOGY.

HYGIENE AND QUARANTINE.

DRAINAGE AND SEWERAGE IN RELATION TO THE PREVENTION OF DISEASE.

{35}

GENERAL MORBID PROCESSES.

INFLAMMATION; THROMBOSIS AND EMBOLISM; EFFUSIONS; DEGENERATIONS; TUBERCULOSIS; MORBID GROWTHS.

BY REGINALD H. FITZ, M.D.

GENERAL MORBID PROCESSES.

Disease is to be regarded as representing the result of a series of processes called morbid or pathological, from the fact that they are manifested by disturbances in the organism.

The processes concerned are the same in kind as those essential to health, but they are modified in time, place, or quantity.

Morbid processes, therefore, are to be considered as modified physiological processes tending to cause disease.

All physiological processes are subject to certain variations which tend to produce disturbances in the functions of the body. In the healthy organism this tendency is checked by the automatic regulators of the functional activity of the various organs, to the importance of which Virchow long ago called attention. By their action the influence of external agents is controlled within certain limits. The lids close and prevent injury to the eye. Sneezing, coughing, and vomiting bring about the expulsion of noxious irritants. Sweating aids in neutralizing the injurious effects of exposure to high temperatures. Rapid respiration permits a sufficient cleansing of the blood in rarefied atmospheres. When the limits, within which the regulation of physiological processes is possible, are exceeded, such processes become pathological and disease begins. A morbid process, therefore, is usually incapable of recognition till disease is present. It may exist and disease be unsuspected and denied. A diminished blood-supply may be one link in the process which eventually leads to the production of disturbances. {36} Another link is to be found in the fatty degeneration resulting from this lack of blood.

Such a degeneration may have long existed in the walls of a blood-vessel, and yet the individual appear in the best of health. The sudden rupture of the weakened wall results in death or disease. With the manifestation of the disturbances which render the condition of the vessel obvious the individual is said to be diseased.

In most instances, however, the morbid process makes itself early apparent. Disturbances of nutrition, formation, or function soon become sufficient in quantity to attract attention from the resulting discomfort, and the presence of disease is then recognized. The latter is thus essentially a conventional term, and begins when the morbid processes occasion a sufficient degree of inconvenience.

The process is never at a standstill. It either tends toward a return to the physiological conditions, or its course is in the direction of their destruction. As physiological processes are absolutely dependent upon the vitality of the elements of the tissues, so those which have become pathological cease to exist with the death of such elements. In the dead body there is no disease, although its results remain, and furnish the most efficient means of identifying the processes which occasioned them.

In the study of morbid processes, therefore, one must appreciate the normal conditions and manifestations of life in the individual. Physiological laws govern pathological phenomena, and the latter must always be submitted to the tests furnished by the former.

Just as little, however, as the study of anatomy familiarizes the student with the anatomical changes resulting from diseased processes, does the study of physiology accustom the student to the features of disease. Pathological processes must be studied by themselves and for themselves, although the means which are employed may be the same as those used in physiological research.

It is evident that the exactness of method which is the demand of the physiological investigator cannot be secured by the pathologist. The material of the latter lies farther, beyond his control. Nevertheless, much of the ground to be gone over is common, and the object sought for is essentially the same--the knowledge of the conditions necessary to maintain life.

In an introduction to the study of disease there are certain processes which deserve early recognition. They are both the cause and the result of disease, and may occur in various diseases, either limited to one organ or present in a series of organs. Their treatment at present obviates the necessity of repetition, and prepares the reader for the special consideration of their occurrence in the various structures and systems of the body.

These processes are named in virtue of some prominent characteristic, and each is made up of a complex series of conditions and disturbances. In part, they represent modifications in the circulation of blood and lymph; in part, they consist of nutritive derangements, whose consequences appear as the various degenerations, or as the additions to the body, the new formations.

The processes and groups of processes in question are those included under the following heads: inflammation; thrombosis and embolism; effusions; degenerations; tuberculosis; and morbid growths.

{37} Inflammation.

Inflammation is characterized now, as in the time of Galen, by the presence of redness, heat, swelling, and pain. The disturbance of function, added to modern definitions, is to be regarded either as a result or a cause, or both, of the variously modified physiological processes whose sum is the inflammation.

The redness of inflammation is obviously dependent upon the presence of an increased quantity of blood. This is readily apparent in the direct observation of the blood-vessels of an inflamed, transparent part of the body, as the mesentery of the frog or rabbit, or the tongue and webbed foot of the former animal. The redness of inflammation consequently demands the presence of blood-vessels in the affected region, and becomes all the greater the more vascular the part--i.e. the richer it is in such vessels.

Redness does not suffice for the existence of inflammation, for it may be found in the absence of other evidence of the latter. The diffused redness, often extensive, of birth-marks, that from venous obstruction or temporary congestions, from vaso-motor disturbances--the section of the sympathetic furnishing a well-known instance--are examples of non-inflammatory redness. Inflammation may even be present without redness, as may be constantly observed in the occurrence of parenchymatous inflammation and of the chronic interstitial varieties.