Inflammation (a process which occurs in the progress of many diseases, and which is also produced by wounds and the presence of foreign bodies acting as irritants. There has always been considerable controversy as to the nature of inflammation, some regarding it strictly as a morbid process, although often accompanying restoration or healing, while others contend that it is essentially a natural and healing effort, the morbid conditions which may accompany it not being a part of the true inflammation, but the cause of it; in other words, that it is an attendant on that vital force which has so long been known under the name of vis medicatrix naturae, being a conservative process employed by the nervous force which has been excited to action by a hurtful presence. Others again look upon the results of the process as determining whether it is morbid or healthful. Hippocrates regarded inflammation, like many of the symptoms of diseases, as a condition instituted by nature, or the the essence or productive power of nature, for the purpose of restoration, and his practice was based upon this theory. Stahl, the elaborator of the phlogiston theory in chemistry, imagined an agent analogous to Hippocrates's i dwelling in the human body, which he called anima, possessing a species of intelligence by which it could institute processes for the expulsion of hurtful intruders. Van Helmont had a similar theory, to which he added the necessity of two circumstances for the development of inflammation : the action of stimulants on parts having sensibility, and an increased activity of the arterial system, followed by redness, heat, swelling, and pain in the parts. He compared the activity of the stimulus to that of a thorn, •which gave alarm to the archaeus, who immediately caused an increased flow of blood to set up a defence and a reparative process. Boer-haave attributed the swelling and obstruction to a change in the texture of the blood, which he maintained grew thicker and more viscid during inflammation, acquiring what he called a state of lentor. He supposed also that the increased action of the arteries forced larger particles of the blood into vessels too small to transmit them, constituting what was termed an error loci.
Cullen, in place of the doctrine of error loci, proposed that of spasm and contraction of the capillary vessels, and taught that the system at the time possessed a peculiar condition, which he called diathesis phlogistica, consisting in an increased tone or contractility of the muscular fibres of the whole arterial system. Vacca, an Italian, about the middle of the 18th century, proposed a theory which was advocated by Mr. Allen of Edinburgh, and which contained an opposite idea, viz., that there was a want of tone or loss of power from which there arose a stagnation of the blood and a dilatation of the vessels of the part. John Hunter taught that the blood had a vitality of its own, and to support his doctrine cited the property of spontaneous coagulation. He says: "There is a circumstance attending accidental injury which does not belong to disease, viz., that the injury done has in all cases a tendency to produce both the disposition and the means of cure." - The general process of acute inflammation may be described as follows: If a translucent vascular membrane, as the web of a frog's foot, is sufficiently irritated by scratching it or pricking with a hot needle, there may be observed with the microscope a contraction of the capillary vessels, followed very soon by a dilatation.
It is maintained by some that during the contraction the circulation is increased in rapidity, and that it is diminished during dilatation; while others maintain that the contrary action takes place in both cases, that is, that the circulation is slower in the first stage and faster in the second. This difference of opinion has arisen from not making the observations under precisely the same circumstances. When a capillary is enlarged throughout its whole length, the circulation will be for a short time more rapid than natural; and when it is constricted for a considerable distance, it will be slower; but if it be contracted in some places and dilated in others, the blood will move slower in the dilated places and faster in the contracted ones, as might naturally be expected from a consideration of ordinary hydraulic principles. After a time, however, the circulation in the dilated vessels becomes slower, and at the same time oscillating, and at last ceases, the vessel becoming distended with colored corpuscles. There is then an exudation of liquor sanguinis through the walls of the vessels, and occasionally, in consequence of their rupture, extravasation of blood corpuscles takes place.
The oscillation of the blood, which immediately precedes stagnation, has by some been attributed to arterial contraction and dilatation, while others have referred it to a rhythmical contraction and dilatation in the veins, which has been observed by Wharton Jones. In the natural circulation the colored corpuscles roll forward in the centre of the vessel, the space between them and the cell wall being occupied by the liquor sanguinis and a few lymph corpuscles. In young frogs the lymph corpuscles are numerous, and under irritation are said to increase and in that way impede the circulation; but in old frogs the same changes occur without the presence of lymph corpuscles. When stagnation or "stasis " takes place, it constitutes what is called the stage of congestion. If the morbid process continues the vessels may burst, or the liquor sanguinis may transude through the walls, without rupture, into the surrounding tissue. This constitutes exudation. The contraction of the capillaries in the first stage and their dilatation in the second are accounted for by supposing them to have the power possessed by involuntary muscular fibres, and John Hunter supposed that they possessed muscular power.
It is known that they have permanent cell nuclei, similar to those of the involuntary muscular fibres of the intestines. Mr. Lister has found that fusiform cells, capable of contraction, are placed transversely around the vessels, which explains the fact that, like intestinal muscular fibres, they may be excited to contraction by mental emotions or by local applications. The recent observations by Claude Bernard and others of the effects produced by dividing the large sympathetic nerve trunk of the neck are cited by Dr. John Hughes Bennet as confirming the theory. It has been found that when innervation from whatever cause has taken place in a part, it is more prone to pass into the condition of inflammation. In regard to the four cardinal symptoms, as they have been termed, of heat, redness, swelling, and pain (the rubor, calor, cum tumore et dolore of Celsus), which were always enumerated by the older writers as constant, it has been found that some of the most fatal cases of inflammation are attended by only one or two of them, and in some cases not one of them has been present.
The latent pneumonia of old people is thus graphically described by Dr. Bennet: "An old man may suddenly lose his appetite and strength; his respiration becomes hurried and feeble; his chest on examination is dull on percussion; mucous rattles are heard by the ear, and he dies. On opening his body gray hepatization has attacked the lungs, which are infiltrated with pus. He has from first to last had no pain; there has been no heat; on the contrary, the temperature was diminished; no redness nor swelling is anywhere detectable. Not only, therefore, are the cardinal symptoms not characteristic of inflammation, but the idea that such is the case has led to the most mischievous results in practice." He maintains that irritation of texture, contraction or dilatation of the blood vessels, capillary haemorrhage, serous effusion which constitutes dropsy, and stoppage of the sanguineous circulation, are only accompaniments of inflammation; and that its essential condition is exudation of liquor sanguinis. Dr. Alison observes that a precise notion of inflammation is obtained by including with the four cardinal symptoms a tendency to effusion of new products capable of assuming the form of coagulated lymph or purulent matter; but Dr. Bennet maintains that the tendency cannot be separated from the act itself, and that it is only when the exudation has taken place that there is proof that the tendency existed.
The objection to this view is that inflammation may take place in non-vascular parts; to which Dr. Bennet replies that the changes which occur in these parts when irritated are widely different from those in vascular parts, and should not be confounded; and moreover, that what has been called parenchymatous inflammation is not true inflammation, which term should only be applied to that perverted action of the vascular tissues which produces an exudation of the liquor sanguinis, and that other results of irritation are simply congestion, or increased growth or hypertrophy. As to the terminations of inflammation, Dr. Bennet divides them into two, depending upon whether the exudation lives or dies. If it continues to live, it constitutes a molecular blastema, in which new growths, temporary or permanent, spring up according to the molecular law of development, such as pus and adhesive lymph. When, on the other hand, the exudation dies, three things may follow: 1, rapid death, with chemical decomposition, producing mortification or moist gangrene; 2, slow death, with disintegration of the tissues, causing ulceration; 3, what may be called a natural death, in which the exudation is broken down, liquefied, and absorbed, or in other words, resolution.
When the exudation lives, it undergoes vital transformations which are greatly influenced by the condition of the system, whether it is healthy or diseased. In the healthy condition, when the exudation takes place on serous membranes, like the pleura, it has a strong tendency to form fibrous tissue; when it occurs on mucous membranes, or in areolar tissue, it is generally converted into pus corpuscles; when it occurs in dense parenchymatous organs, such as the brain, it has a granular development; and when it is poured out after wounds or injuries, the superficial portion is transformed into pus corpuscles, while the deeper seated is converted by means of nuclei and cells into nucleated and cell fibres, which ultimately form the cicatrix. The microscopic examination of a recent exudation of liquor sanguinis will reveal the appearance of bundles of minute filaments mingled with corpuscles. The filaments are formed by a simple precipitation of the molecules, like those which are developed in the buffy coat of the blood, and are from 1/14,000 to 1/10000 of an inch in diameter. Bundles of them cross each other, and in time assume the appearance of dense fibrous tissue.
The corpuscles at first are transparent, but soon become distinct, and are seen to be composed of a cell wall enclosing from three to eight granules. They vary in size from 1/1300 to 1/1000, and the granules from 1/14,000 to 1/10,000 of an inch in diameter, and are termed by Dr. Bennet plastic corpuscles. They are not pus, although Lebert called them pyoid, and it is generally believed that they are an intermediate or arrested stage of the degeneration of plastic lymph from its fibrillated development to pus. These plastic corpuscles after a time mostly disappear, some remaining in the form of permanent nuclei. After a time the surface of the exudation becomes villous, and loops of blood vessels penetrate the villi, by which the serum separating the surfaces is absorbed, so that they come together and unite, forming dense adhesions, which are often found in post-mortem examinations after inflammations of serous membranes. When the exudation takes place upon a mucous membrane, it may have the form of a fibrous mass, as in croup or diphtheria, but more often that of an opaque creamy fluid called pus. When it is poured into the meshes of the areolar tissue, or into the substance of the brain, it forms abscess.
Pus corpuscles are of a globular form and yellowish color, varying from 1/2000 to 1/1200 of an inch diameter. They are composed of a cell wall containing from two to five granules, which are about 1/6000 of an inch in diameter. When a microscopic examination is made of a recently formed granulation on a healing wound, there will be observed around the looped extremities of the capillary vessels fibrous tissue in the process of formation containing plastic corpuscles, while pus corpuscles will be found developed on the surface. As the fibrous tissue becomes more dense the pus diminishes, and at last ceases, the fibrous tissue attaining a certain growth, and after a time contracting and forming a cicatrix. All pathologists agree very nearly as to the changes which are here described, but many, among them Virchow, Billroth, Simon, and Sir James Paget, believe that inflammation is not restricted to one act; that congestion and determination of blood may be considered its first stages; and that it may exist and pass away without exudation.
They ask, if inflammation is produced by irritation, when this is in process of operation, where shall the dividing line be placed between the departure from health and the commencement of inflammation? It is also objected that the web of a frog's foot, as being a part of a cold-blooded animal, is not a proper subject for the experiment, and accordingly a bat's wing has been substituted. Sir James Paget thinks that in warm-blooded animals stagnation will be found in only the most severely inflamed parts, while in the others retardation only exists. The difference of appearance in the red corpuscles in natural human blood and in that drawn during inflammation is worthy of notice. In healthy blood they have a tendency to run together in rows like a pile of coins tipped over, while in blood drawn during inflammation there is a tendency to run together in masses, leaving larger spaces of liquor sanguinis between them. According to present views, the effect of inflammation in recent wounds is not to promote direct healing, but to prevent it. "When a fresh wound in a healthy person is closed and the blood forced out from between the cut surfaces, the severed capillaries unite directly, without, it is maintained, the exudation of plastic lymph; but if the lips of the wound are allowed to gape, an inflammatory action takes place, plastic lymph is poured out, and granulation follows in the manner above described. - The conservative action of inflammation may be observed in the healing of punctured or gun-shot wounds of the cavities of the body. "When a puncture has been made into the abdomen, the great danger lies in the development of extending inflammation of the peritoneal membrane, and it is greatly increased if any of the contents of the intestines are poured into the space between its surfaces.
The irritation produced by the injury excites adhesive inflammation between the different layers which compose the walls of the abdomen, and thus a simple channel is established between the exterior and interior, which in course of time may heal by granulation and suppuration. Severe cases of inflammation, as that which supervenes upon a compound fracture, are attended with marked characteristic symptoms. There is a feeling of heat, and of alternate heat and chilliness; the skin and mouth are dry; the pulse becomes rapid and the patient restless; the urine becomes scanty and more highly colored than natural, and great thirst is experienced; the tongue is dry and coated with a whitish fur; sleep is absent or greatly disturbed, and a degree of delirium comes on, more especially at night; there is usually constipation, but when the bowels act, which generally requires medicine, the excretions are very offensive; there is great swelling and tenseness of the tissues of the injured part, which when it subsides is attended with a remission of the constitutional symptoms; the skin and mouth become moist; the delirium and restlessness pass gradually away, and the patient sinks into a slumber. - The causes of inflammation are various, and may be divided into two classes, predisposing and exciting.
The predisposing causes embrace constitutional and hereditary tendency, food, climate, season of the year, and habit of body. The exciting causes are poisonous substances, including the poisons of different diseases; irritants, such as cantharides, pepper, mustard; caustic escharotics, strong acids, very hot and cold bodies, wounds, and also exposure of the person to wet and cold, or to sudden changes of temperature. Excessive mental excitation is a cause of inflammation of the brain. Inflammation may be acute or chronic. That which has been described is acute. After a subsidence of the intensity, if the action continues, in consequence of any source of irritation remaining, or from a want of tone of the parts, it becomes chronic, and from the latter cause the symptoms sometimes assume the chronic form from the outset. Inflammation is said to be healthy or unhealthy. If restoration takes place during the process, it is said to be healthy; but if there is wasting or destruction of tissue, as in ulceration or mortification, it is said to be unhealthy. It may also be common or specific; the latter term being employed to denote that which is caused by certain contagious poisons, such as smallpox, gonorrhoea, and erysipelas.
It is sometimes called after the tissue in which it occurs, as mucous or serous inflammation. Inflammation of particular organs is usually designated by adding the termination itis to the anatomical name of the part affected, as laryngitis for inflammation of the larynx, gastritis for inflammation of the stomach, cerebritis for inflammation of the brain; but the old nomenclature is often retained, as pneumonia for pneumonitis, quinzy for tonsillitis. No nomenclature, however, is better than the employment of the word inflammation, together with the name of the organ or part inflamed. Inflammation is most likely to attack children under ten years of age, nearly one half of the mortality of the race occurring during these years. Inflammations of the pleura, brain, liver, and membranes of the heart are more, frequent after the age of manhood. Spring is more favorable than any other season to the development of inflammation, and moist weather than dry, as is exemplified by the great rarity of inflammatory diseases in the regions bordering on the Pacific coast. The color acquired by an inflamed part differs with the degree of inflammation and the organ affected. The tendons and ligaments are seldom reddened.
The fibrous membranes, like the pericardium, the dura mater, and the sclerotic coat of the eye, acquire a lilac or purple hue inclining to blue. The mucous membrane of the intestines first presents a bright red, but during the progress of the disease becomes a dark violet or a black, especially when passing into gangrene. These changes may be seen in. the mucous membrane of the throat in an attack of malignant scarlet fever. In inflammation of the pleura and peritoneum (serous membrane) the color commences with a lilac, which afterward passes to scarlet, brownish, or violet. In the arachnoid, the serous membrane of the brain, the discoloration is slight, the chief sign of the inflammation being the serous effusion. The salivary glands assume a pink color, the kidneys a deep violet, and the lungs vary from a light rose to a deep purple. The alterations in color are owing in a great degree to the carbonization of the blood which is caused by stagnation and want of aeration. The continuance of inflammation in an organ prevents nourishment, and consequently after the swelling subsides it will be smaller. The wasting of the system during fever is an analogous example. - Treatment. This is divided into local and general.
The local treatment of an inflamed wound consists in reducing the temperature by the application of cold or cool affusions, depending on the intensity of the action. Cold water may be allowed to drip from a vessel properly arranged and suspended above the wounded part, which is covered with a layer of linen; or cloths may be moistened with cool water and laid upon the wound; care in either case being taken to preserve an even temperature, and not by an intermission of the application to allow reaction to take place. The general treatment consists in a plain diet, principally of liquid food, which however should contain enough nourishment to support the strength of the patient; and he should be allowed to partake freely of water and cooling drinks, although at times warm drinks of weak tea may be allowed. To relieve constipation laxatives may be given. In inflammation of membranes and organs accompanying diseases such as pneumonia and like various forms of fever, contagious or not, there is almost always a want of saline constituents of the blood, the result of waste, and this condition may often be remedied by the administration of saline medicines, such as the bicarbonates of soda and potash.
In fevers generally the parched condition of the mouth and throat and dryness of the skin are caused by a want of secretion of the mucous follicles and sudoriparous glands of the skin; and these alkaline salts in conjunction with the free administration of water are well calculated to restore a healthy action. Local bleeding by cupping and leeching may often be resorted to with benefit; but general bleeding, which was formerly practised to a great extent, is now almost wholly abandoned.