Elements of Surgery

by Robert Liston

Inflammation may be defined to be, an unnatural or perverted action of the capillary blood vessels of an organ or part of the body, attended with redness, throbbing, swelling, pain, heat, and disorder of function, as well as with more or less disturbance of the system.

Every part of the body is liable to inflammation; and some writers have divided this action into different kinds, according to the particular tissue which it chiefly involves. But it appears to be always of the same character, though modified by various circumstances, such as the tissue in which it occurs, the state of the constitution, the exciting cause, and the intensity of the action.

The usual division of the subject, into Acute and Chronic, is that which it is here proposed to adopt. The term Chronic Inflammation is more properly applicable to a consequence of the Acute: but it is at the same time true, that morbid actions proceed more slowly in some constitutions, and in some parts of the body, than in others; and that changes of structure and morbid products, such as generally result from inflammatory action, even occasionally occur, without the prominent symptoms of inflammation being experienced by the patient or detected by the practitioner.

The term Morbid is used in contradistinction to what is called Healthy Inflammation; but inflammatory action is generally connected, more or less, with a diseased or disordered state of some part of the body. In many circumstances it is highly necessary that a certain degree of incited action of the vessels should occur, and continue for a certain time; as during the uniting of fractures, the adhesion of wounds, and the healing of some sores—and thus far it is healthful: when, however, the action becomes excessive, it must, for this reason, be considered morbid, as it frustrates the natural reparative process; if the action, in fact, proceeds farther than is necessary for reparation, it becomes a disease, and leads to absorption or destruction of parts. In animals possessing the greatest powers of reparation, inflammation, it appears, does not take place at all, or is very slight, and scarcely ever proceeds to suppuration.

Redness is the first sign of inflammation to be considered; this is observed, in the living body, on the surface, or at the extremities of those canals which terminate externally. The inflamed conjunctiva affords a conspicuous example of this appearance. In a subject that has suffered from an internal inflammatory attack, a good opportunity is frequently afforded of observing the enlarged and injected state of the vessels on which the red colour depends. But inflammation may have existed to a certain degree, and yet the parts may be pale, from the capillaries having emptied themselves into the veins immediately after the patient’s death. The paleness may be also in part caused by the influx of the red globules being impeded immediately after death, or when the patient is in articulo mortis, in consequence of the contraction of the vessels, which is well known to occur at that period.

It has been said that redness is not essential to inflammation; for serous vessels may be altered in size and function by this action, and yet not be sufficiently dilated to receive the red globules of the blood. And, again, that serous vessels may be enlarged so as to admit the red globules; and a part that is colourless when in the healthy state may, in consequence, assume a highly red hue when in an inflamed condition. This may be observed in the cornea lucida, which, when violently inflamed, is pervaded by numerous vessels, visible to the naked eye, distended with red blood, ramifying over the whole of it, and freely inosculating with each other. Some have even supposed that these vessels are newly formed, in consequence of inflammatory action. This opinion is, however, erroneous; as the vessels existed in the cornea previously, and are only increased in size, so as to admit of the accumulation of a sufficient number of red particles to render the vessels visible. The speedy, and, in many cases, instantaneous, appearance of red vessels where they could not previously be observed, decidedly overturns the opinion that new vessels are in such a case formed. New vessels are seldom formed, unless after a breach of structure, or in cases where morbid deposits become vascular. There is no proof of the existence of mere serous vessels in the human body, as any one may ascertain who is accustomed to examine the capillaries with a good microscope. Vessels which are so small as to admit only a very few, say one, or at most two rows of globules, would, of course, appear colourless, and these are what have been called serous vessels. The globules of blood are so small as to be invisible to the naked eye; and vessels carrying only one series of them would appear colourless. No vessels belonging to the sanguiferous system have ever been observed less in character than a blood globule; and this, so far as I have been able to observe, is, as nearly as possible, 1/3000 part of an inch. They appear to be flattened discs; and whether those of the human body have a central nucleus or not, seems, as yet, very doubtful. The

globules are here shown upon a scale of 1/4000 part of an inch, linear, and in different positions. They are represented, as seen in the greater number of microscopes, having a central nucleus. Whether, in the blood of mammiferous animals, or not, this is an optical deception, is not very clearly made out; but in that of reptiles the nucleus is easily demonstrable. The redness then is not from error loci, or in consequence of red particles flowing where none flowed before, but from the capillaries becoming distended and dilated with an unusual quantity of blood, which is stagnated in the central part of the inflamed neighbourhood, the inflammatory focus.

Throbbing, to a greater or less degree, is always felt in an inflamed part by the patient; and it is frequently so distinct as to be readily perceived by an attentive examination. This arises, probably, from the stagnation of blood in the vessels of the part over-excited, and principally affected by the disease or injury, causing an increase in the collateral circulation; and it is this rapidly increased action around that gives rise to the signs and symptoms, and constitutes, in point of fact, what is known and recognised as inflammation. The sensation of throbbing is not, however, produced entirely by the action of the capillary vessels, but in consequence, also, of the larger trunks in the neighbourhood sympathising with these capillaries, and so having their action increased also. The obstruction of the capillaries in the early stage of inflammation must necessarily cause a greater force of the heart to be expended on the trunks leading to such capillaries; hence the greater impulse and velocity of blood in the circumferential and patent vessels. In fact, when the inflammatory action is extensive or severe, or when the part affected is of much importance to life, the whole circulating system is disturbed, and thus arises the sympathetic excitement of the constitution.

The incited action of those vessels in the more immediate vicinity of the inflamed part is well marked in cases of Paronychia. There the digital, the radial, and ulnar arteries, with their branches, beat more violently than usual; and with much greater force, though not more rapidly, than the vessels in other parts of the body.