Elements of Surgery. Robert Liston

other causes are generally in operation at the same time, as will be afterwards more fully explained.

      Pus was formerly regarded as irritating and corroding, and was therefore carefully removed from every granulating sore; but purulent matter, though it may prove a source of irritation to the neighbouring parts, does not disturb the surface which secretes it, but, on the contrary, protects the tender granulations, and acts as a temporary cuticle. A crust is formed by the evaporation of the thinner part of the fluid; and we frequently see small sores healing rapidly when thus protected. In some instances, we adopt the hint given to us by nature, and produce a scab by the application of powders, lunar caustic, &c.

      The discharge does not always consist of laudable purulent matter. Pus formed in the diseased part itself has particular characters, according to the tissue involved; thin and greyish in bones, opaque and caseiform in cellular tissue, flocculent in serous, and greenish and thready in mucous membranes; it is said to be reddish in the liver, and yellowish-grey in muscles. Its sensible properties are various, often very offensive when proceeding from a cavity containing decayed bones, and it degenerates in consequence of disturbance of the constitution, or of the part affected. It is also frequently suppressed, in consequence of over-action in the vessels of the part, or from debility, partial or general.

      Suppression of a purulent discharge is to be regarded as an untoward symptom, fraught with considerable danger, being generally followed by the most violent constitutional disturbance. Certain cases would seem to warrant the belief that a species of metastasis occurs; that the matter is absorbed, and again deposited in some other part, perhaps of the utmost importance in the animal economy. The danger arising, when the pus is not separated from the blood, has already been adverted to. No wonder, if from any cause it does not escape by its accustomed channel, that an effort should be made to deposit it somewhere else, for the temporary relief of the system. The most vascular parts are commonly chosen, as the lungs, spleen, and liver. In the cavities of joints, also, matter is often found in great quantities. This is sometimes indicated by the occurrence of tenderness and swelling for only a short period previously; but, in other cases, its presence has never been suspected. In purulent collections, after wounds from accident or operation, on the suspension of the discharge, the patient becomes affected with severe constitutional irritation, and gradually sinks; the existence of purulent depôts in the viscera of the chest or abdomen, being perhaps not indicated by any, unless very equivocal, symptoms, and these appearing only a short time before dissolution. A late writer has endeavoured to connect this with inflammation of the veins; but such an opinion is not borne out by observation, although the two circumstances may occasionally coexist. In many cases the veins of a limb are found filled with pus, yet their coats present no marks of inflammatory action having existed in them. Their mouths are open in the wound, from failure of that healthy action by which they would have been closed by coagulated lymph, and the matter appears to be taken up by them as secreted.

      From the discharge varying according to the state of the system, the latter can in general be accurately ascertained by examination of the sores which afflict the patient.

      In collections of matter not far removed from the surface, the most superficial, and generally the most dependent, portion of the parietes appears inflamed; its inner surface is gradually absorbed; and, when it has thus become attenuated, a portion of the integument sloughs or ulcerates. A communication is established with the diseased parts, through the external surface, thus providing an aperture for the evacuation of the matter—of extraneous substances—or of parts of the body which have either mortified, or otherwise become useless to the system. In such collections, more especially if deeply seated, the matter generally seeks the surface, or extends in the course of the bloodvessels.

      Cold abscesses, as they are called, often contain as much flaky fibrinous matter as true pus: hence one of the signs of inflammation, swelling, is absent; the fibrin being discharged instead of having been added to the neighbouring parts.

      As formerly remarked, suppuration occurs much more readily in some constitutions than in others; and patients peculiarly liable to the formation of abscesses, without any great degree of previous excited action of the bloodvessels, are said to labour under Struma or Scrofula. These terms are by some used to denote a distinct or specific disease, while others consider them merely as a peculiar state of the constitution.

      The strumous diathesis is said to be marked by hair and irides of a very light colour, and by the skin being of a peculiar white hue; but, in some instances, the complexion is unusually dark and sallow. The upper lip generally presents a swollen appearance, as also the columna and alæ of the nose. The organization throughout is delicate, and the patient is frequently of a handsome, though infirm, structure.

      Constitutions, in every respects strong and originally vigorous, may, from various causes, become weak, and present many of the symptoms usually termed scrofulous. I recollect a young patient, born of healthy parents, who had enjoyed excellent health, becoming covered with ulcers and chronic abscesses, in consequence of exposure to cold during menstruation.

      To the continued irregular and imprudent exhibition of mercurial alteratives, as they are called, may be attributed the cachectic and scrofulous constitutions of many thousands of patients of all ages.

      The strumous diathesis is said to depend upon a want of balance, or proportion, between the solids and circulating fluids. Want of action and power in the organs forming and circulating the blood, disordered digestion, and various other circumstances which it is unnecessary to detail, have also been considered as causes of this state of the constitution.

      Many suppose that the diathesis, or a disposition to the diathesis, is always congenital; and this opinion is supported by the majority of cases. However, certain circumstances produce a scrofulous habit of body in patients who previously appeared to be vigorous and healthy, and untainted with any peculiar disposition to disease. Of these predisposing causes may be mentioned, a poor diet, an impure atmosphere, exposure to damp and cold, inattention to cleanliness, the latter circumstance acting sometimes by producing local irritation: in fact, whatever deranges the general health, seems, in many cases, to induce the strumous diathesis. Some constitutions are incapable of resisting any unusual incitement of the vascular system, or of repairing the consequences of the action, or of any injury, in whatever way inflicted. In such individuals, all the parts of the body are deficient in power—some, however, are more so than others, and, consequently, more readily give way; thus, the lymphatic system, the mucous membranes, the skin, the bones and their coverings, generally suffer in the first instance.

      Glandular swellings of all kinds, and in all situations, often followed by suppuration, are apt to occur from irritation of various descriptions, but more so in constitutions originally weak, or which have become debilitated by disease or any other cause. The larger glandular tumours are formed by congregation and agglutination of the smaller ones, and by the deposition of adventitious matter in the connecting cellular substance; separation of the smaller tumours composing these, naturally, or under the use of deobstruents exhibited internally, or applied to the surface, is a highly favourable sign, and equally encouraging to the surgeon and the patient.

      Dentition, the presence of carious teeth, of stumps of teeth; excoriations behind the ears, eruptions on the scalp, affections of the lining membranes of the eyelids, mouth, or nose, of the skin of the face, are daily found giving rise to glandular swellings in the neck; whilst irritations in the urethra, excoriation or slight disease about the anus, corns or sores about the feet or toes, produce similar affections of the glands in the groin. Such sources of irritation are, of course, to be looked for in the first instance, and will often materially influence the diagnosis, though too much is occasionally attributed to their influence. Such glandular tumours, however, sometimes occur spontaneously, or, at least, without any evident cause. They have been mistaken for other diseases, according to their situation—for aneurism, hernia, or venereal bubo; the latter mistake is often committed unintentionally by the ignorant, or designedly by the unprincipled.

      Tumours formed by the enlargement of glands are frequently productive of dangerous consequences. If situated in the neck, they may render breathing and deglutition extremely difficult, and in the event of their suppurating, the purulent matter may be discharged into the trachea or