is a process by which a peculiar fluid termed pus is formed in the substance, or from the surface of parts of the body.

When purulent matter accumulates in the part affected, it is termed an alscess, which is distinguished and divided into several kinds, acute, chronic, scrofulous, etc.

The texture in which suppuration seems to be most readily produced by a certain degree of inflammation is mucous membrane, whether this lines excretory ducts or canals, or covers the inner surfaces of the respiratory or urinary organs. In a few hours after an irritating cause has been applied to these surfaces, the physical and chemical qualities of the fluid which they secrete in their natural state are changed.

From being a tough viscid substance, not easily miscible with water, the mucus of the nose and bronchi becomes, during an attack of inflammation, very readily miscible with water, and of a yellowish-white colour and fluid consistence. If in this state the secretions from these membranes be examined with the microscope, it will be found to contain small globules similar to those which are seen in the blood, and these globules are found to increase in number in proportion to the degree and continuance of the inflammation.

Suppuration may be readily produced in the skin by whatever excites inflammation in that texture, or causes a separation of the cuticle; we have examples of this fact in blisters from canthariues, and in vesications from superficial burns, If the cuticle covering a recent blister or burn be removed, and the true skin exposed to the irritation of stimulating substances, pus will soon be discharged from the abraded surface. Suppuration can be kept up in the skin for an indefinite length of time by perpetual blisters. Here ulceration is seldom observed, and consequently, in the skin, loss of substance is by no means necessary for the production of pus.

If the cutis be divided, as in a wound, or a portion of it removed, as in the extirpation of tumours, and either the air or any other external body be permitted to remain in contact with the divided surfaces, the process of suppuration is speedily induced in the adjacent cellular texture. After the hemorrhage which takes place from the small vessels has ceased, an oozing of a fluid, at first resembling serum, occurs, which is gradually changed into pus. But in this case the surface of the wound is previously covered with a layer of coagulable lymph, which is penetrated with bloodvessels, and gradually raised into the little red eminences called granulations.

Appearances similar, though slighter in degree, are observed in cutaneous suppuration, giving probability to the opinion that in inflammation a vascular surface is produced previously to the formation of pus in a cellular substance, and perhaps also in cutaneous texture. However, no new vascular surface is generated in the inflammation of mucous membrane. Thus we see that in the formation of pus in raucous membranes, cutaneous textures, and exposed cellular substances, no ulceration, no breach of substance is essential; but that, on the contrary, in two of these textures, the cutaneous and cellular, there is an addition made to the parts by the exudation of coagulating lymph, which becomes organised.

The surface of an inflamed serous membrane soon becomes covered with a very thin layer of an albuminous and gelatinous substance, and when this is removed, the membrane is found to have lost its smooth polish. This deposit gradually becomes thicker and more adherent, and forms the rudiment of a false membrane. It is almost constantly accompanied with a serous or sero-purulent effusion. This organised matter has been proved to consist of two parts, one concrescible and adhesive, formed of fibrine; the other fluid, and contained in cells of the former, consisting of albumen. It constitutes what is usually termed coagulable or coagulating lymph, and by undergoing certain modifications it appears to be converted into pus. Thus, when adventitious membranes do not become organised, they are generally softened down into pus. Pus is sometimes formed within a muscle, and here it seems to be deposited in the intermuscular cellular tissue, the muscular fibre itself being apparently incapable of suppuration.

Purulent matter is met with in all the parenchymatous tissues, either in the form of abscess or of purulent infiltration, as for instance in the lungs, liver, spleen, kidneys, etc, a circumscribed or encysted abscess being more common in the liver, a purulent infiltration in other organs.

Again, mucous membranes are more prone to suppuration than serous ones, in which last there is a far greater tendency to the adhesive inflammation.

Pus is also sometimes met with within the bloodvessels and lymphatics, and even in the heart itself. It has been detected in veins which return the blood from parts in which pus has been collected, as well as in lymphatics, originating in textures in the state of suppuration. In phlebitis its presence in the veins, and its mixture with the circulating blood without any preparatory action of the absorbents upon it, are believed to be the principal causes of the frequently fatal termination of this dangerous affection.

Symptoms Of Suppuration

When matter is fully formed in a tumour, there is a change or even a remission of some of the symptoms. The throbbing pain which was so severe on the approach of suppuration from acute phlegmonous inflammation now subsides, and the patient appears dull, with increased pain in part. A conical eminence, or pointing as it is termed, mostly takes place at some part of the tumour, generally near its middle. In this situation a whitish or yellowish appearance is observable instead of a deep red, which was previously apparent, and a fluctuation under it may be discovered on a careful examination with the fingers. Sometimes, indeed, when an abscess is thickly covered with muscles and other parts, the fluctuation cannot be easily distinguished, though, from other concurring circumstances, hardly a doubt can be entertained of there being even a very remarkable collection of matter. An œdematous swelling over the situation of deeply seated abscesses is a symptom which sometimes throws light on cases of this description. When matter is formed upon the natural surfaces of the body which are connected with vital organs, much irritation and disturbance takes place, but when matter is produced upon the surface of a wound, or upon parts of little vital importance, then its formation is often unpreceded by irritative fever.

The constitutional symptoms which attend the formation of pus in the progress of chronic suppurations are generally comprehended under the head of fever already described.