INFLAMMATION is the most important of all the morbid processes that fall under the notice of the physician or surgeon. The most obvious symptoms or phenomena of inflammation, when it attacks an external or visible part, are pain, redness, heat, and swelling, or, in the wordi of Coleus, "rubor et tumor CUM caiore et (Urn's." The general characters of the process will be best understood by an assumed case. If a healthy man gets a splinter of wood or any other foreign body imbedded in any fleshy part, he berrins to experience pain at the part, and this is soon succeeded by redness of the skin, fi.firin and extremely tender swelling at and around the spot, and a sense of abnormal heat. These purely local symptoms are succeeded, if the inflammation reach a certain degree of intensity, by a general derangement of the vascular and nervous systems, to which various names, such as constitutional disturbance, symptomatic or inflammatory fever, pyrexia, etc., have been applied. If the foreign body is extracted, the probability is that all these symptoms will gradually abate until the part at length regains its natural appearance and sensations. In this case the inflammation is said to terminate by resolution, and this is the most favorable mode of termination. If, how ever, the cause of irritation is not removed, or if the intensity of the morbid process exceed a certain point, the following phenomena occur: the swelling assumes a more projecting or pointed form, the part becomes softer, and the skin at its center, which is usually the most projecting part, becomes whiter. There is a sensation of throbbing pain, and if the skin be not divided by the knife. it finally breaks, and a yellow, cream like'fluid, known as pus (q.v.), escapes, after which the symptoms readily abate. This termination is known as suppuration.
If the original injury was very severe, and the inflammation intense, there may be actual death of the part affected. In that case, the red color of the skin becomes purple or greenish black, the pain ceases, and the part becomes dead and putrid. This is mortification. Under favorable circumstances, this dead part, which is called a slough, spontaneously separates from the adjacent living parts by a vital process known as ulceration (q.v.), and the cavity which is thus formed gradually fills up and heals.
The pain may vary from mere discomfort to intense agony. There is usually most pain in those parts in which the tension produced by the swelling is the greatest, as in bone, serous and fibrous membranes, etc. The pain occurring in inflammation is always aggravated by pressure, and by this means the physician can often distinguish between inflammatory and non-inflammatory disorders. The heat is seldom so much increased as the sensations of the patient would lead him to believe; it does not rise above the maximum heat of the blood in the interior of the body. This increase of heat depends upon the increased flow of arterial (or highly oxidized) blood to the part. The rednem depends upon there being more blood than usual in those vessels in the affected part which usually carry rod 'blood; upon the blood containing an increased number of red corpuscles; and upon red blood entering into vessels which, in the normal state. convey colorless fluids only, or which naturally admit so few red corpuscles that they cannot, usually be observed. The 'swelling depends in part upon the distension of the blood vessels, but mainly upon the effusion of various fluids, such as blood, serum, coagulable lymph (or fibrine), and pus into the tissue of the affected part. These fluids are termed the products of inflammation. This coagulable lymph frequently becOmes organized, and many changes, some of a reparative nature (to which a reference will be presently made), and others of a morbid nature, depend upon its effusion.
Numerous observers have attempted to trace the exact phenomena of inflammation, by microscopic examination of the transparent parts Of animals in which the process has been artificially excited. From observation made on the web of the frog's foot and other transparent parts of animals by Wharton Jones, Paget, and others, the following• general conclusions may be drawn.