SUPPURATION is a morbid process which gives rise to the formation of pus (q.v.), as is well known, is one of the commonest products of inflammation. There are two doctrines as to the origin of pus. The opinion universally adopted till very recently was, that it was formed from an excessive exudation of the fluid portions of the blood through the walls of the capillaries; in which exudation, under certain conditions, pus cells were developed. This view is now rejected for the doctrine of Virchow, the emi nent professor of pathology at Berlin, who maintainer that pus-cells are generated from the corpuscles of areolar tissue, which he supposes to permeate nearly every portion of the body. Pus, according to Virchow, is a young tissue in which, amid the development of cells, all solid intercellular •substance is gradually dissolved. A single cell of areola or connective tissue may, in an extremely short space of time, produce some dozen of puss-cells; but the result is of no service to the body, suppuration being, to use his own words, " a pure process of luxuriation, by means of which superfluous parts are produced, which do not require that degree of consolidation or permanent con nection with one another, and with the neighboring parts, which is necessary for the existence of the body." There are two different modes of pus-formation, according as the pus proceeds from epithelium (q.v.) or from connective tissue (see CELLULAR TIssuE). When puss is formed from epithelium, it is produced without any consider able loss of substance, and without ulceration; but when it is formed from connective tissue, ulceration must always exist. The mucous membranes vary in their power of forming pus. A mucous membrane, according to Virchow, is the more qualified to produce pus without ulceration the more completely its epithelium is stratified, those with a single layer of epithelium being less adapted for the production of pus. Thus
the intestinal mucous membrane scarcely ever produces pus without ulceration; while other mucous membranes, containing several strata of cells, are capable of secreting enormous quantities of this fluid without the slightest ulceration (as, for example, the urethral mucous membrane in gonorrhea). .
The above cases of suppuration occur on free or exposed surfaces, and are unac companied with loss of tissue. Deep-seated pus-formation takes place only in connective tissue. The first stage of formation consists in an enlargement of the normal cells, and a division and excessive and rapid multiplication of their nuclei. This is soon followed by division of the cells themselves, and their conversion into true pus-cells. If this process takes place beneath a surface which does not participate in the morbid change, or which is capable of resisting it for a time, an abscess is formed; whereas, when pus cells are poured forth from an exposed surface, we have an ulcer.
Although suppuration is a morbid procees, it often accompanies processes of a bene ficial tendency (such as granulation), and frequently takes the place of other far more morbid processes. It further affords a mechanical means of removing foreign bodies, such as thorns, splinters of glass, etc., from soft parts into which they may have been driven; and it is possible (as some pathologists believe) that the formation of abscesses may sometimes serve to eliminate morbid matters from the system.