This section is from the "Nature Cure: Philosophy and Practice Based on the Unity of Disease and Cure" book, by Henry Lindlahr.
To me the story of inflammation has been one of the most wonderful revelations of the complex activities of the human organism. More than anything else it confirms to me the fundamental principles of Nature Cure, the fact that Nature is a good healer, not a poor one.
Before inflammation can arise, there must exist an exciting cause in the form of some obstruction or of some agent inimical to health and life. Such excitants of inflammation may be dead cells, blood clots, fragments of bone and other effete matter produced in the system itself or they may be foreign bodies such as particles of dust, soot, stone, iron or other metals, slivers of wood, etc.; again, they may be microorganisms or parasites.
When one or more of these exciting agents of inflammation are present in the tissues of the body in sufficient strength to call forth the reaction and opposition of the healing forces, the microscope will always reveal the following phenomena, slightly varying under different conditions:
The blood rushes to the area of irritation. Owing to this increased blood pressure, the minute arteries and veins in the immediate neighborhood of the excitant dilate and increase in size. The distension of the blood vessels stretches and thereby weakens their walls. Through these the white blood corpuscles squeeze their mobile bodies and work their way through the intervening tissues toward the affected area.
In some mysterious way they seem to sense the exact location of the danger point and hurry toward it in large numbers like soldiers summoned to meet an invading army. This faculty of the white blood corpuscles to apprehend the presence and exact location of the enemy has been ascribed to chemical attraction and is called chemotaxis.
The army of defense is made up of the white blood corpuscles or leukocytes and of connective tissue cells which separate themselves from the neighboring tissues. All these wandering cells possess the faculty of absorbing and digesting microbes. They contain certain proteolytic or protein-splitting ferments, by means of which they decompose and digest poisons and hostile microorganisms. On account of their activity as germ destroyers, these cells have been called germ killers or phagocytes. In their movements and actions these valiant little warriors act very much like intelligent beings, animated by the qualities of patience, perseverance, courage, foresight and self-sacrifice.
The phagocytes absorb morbid matter, poisons or microorganisms by enveloping them with their own bodies. It is a hand-to-hand fight, and many of the brave little soldiers are destroyed by the poisons and bacteria which they attack and swallow. What we call pus is made up of the bodies of live and dead phagocytes, disease taints and germs, blood serum, broken-down tissues and cells, in short, the debris of the battlefield.
We can now understand how the processes just described produce the well-known cardinal symptoms of inflammation and fever; the redness, heat and swelling due to increased blood pressure, congestion and the accumulation of exudates; the pain due to irritation and to pressure on the nerves. We can also realize how impaired nutrition and the obstruction and destruction in the affected parts and organs will interfere with and inhibit functional activity.
The organism has still other ways and means of defending itself. At the time of bacterial infection, certain germ-killing substances are developed in the blood serum. Science has named these defensive proteins alexins. It has also been found that the phagocyte and tissue cells in the neighborhood of the area of irritation produce antipoisons or natural antitoxins, which neutralize the bacterial poisons and kill the microorganisms of disease.