Interference with motion or the normal functions of a part is sometimes produced through the proximity of the abscess.
Etiology.—Inflammation due to trau matisms and lesions of all kinds, espe cially the introduction of foreign bodies under the epidermis, are the usual causes of abscess. While blows do not appar ently produce superficial lesions in the majority of cases, the fact remains that an invisible abrasion may be present and serve as a channel for the introduction of the pyogenic organism. The cutaneous glands, through weakened local resist ance, may also become the transmitting media. Any cause removing the epithe lial layer of the mucous membrane may also form the primary etiological factor of an abscess in the membrane or in the submucous connective tissue. Abscesses also arise in connection with the various septic fevers.
tuppuration can oecur in man with out the presence of bacteria. Both in animals and in man suppuration may be clue to the irritation of chem icals. Investigators have shown that suppuration is only a certain stage of inflammation, not a separate qualita tive form of inflammation. The serous formation of blebs and bulhe becomes purulent without the presence of bac teria. Karl Kreibich (Wiener kiln. Woch.. June 13. 1901).
Case of subcutaneous abscesses due to the gonoeocens in a child. 2 years of age. The little patient suffered from typhoid fever, and a few days after ad mission to the hospital developed an acute anterior urethritis, which was proven to be gonorrhceal in nature.
The source of infection could not be Seven and ten days later, respectively, areas of induration ap peared to the left and right of the anus. Both were found to contain pus in which gonocoeci were present. Cershel (Med. Record, Feb. 7, 1903).
Pathology.—While several varieties of micro-organisms are found in the pus of an acute abscess, staphylococci and streptococci are by far those most fre quently observed, the former being usu ally found in circumscribed abscess and the latter in diffuse ones. The first step in the process is increased rapidity of the flow of blood in the part, the vessels be coming engorged and dilated. This is succeeded by slowing of the current and passage through the vascular walls and into the surrounding tissues of colorless corpuscles (leucocytes), a few red cor puscles, and blood-plasma, the latter of which become coagulated and finally softened. One or several cavities are thus formed; but, if the cavities are multiple, the barriers usually soften and a single focus is established. The pus is
composed of the corpuscles which perish in the cavity thus formed, the broken down remains of tissue, and the plasma. At a distance from the location of the abscess the circulation is normal, but, as the diseased area is approached, the slow ing of the blood-current becomes gradu ally more evident, until a zone of living leucocytes is met, forming a protective barrier around the abscess-cavity. The surrounding parts also become permeated with new vessels, and a zone of granula tion tissue (the pyogenic membrane of older writers) is formed. The spread of the suppuration being thus checked, the pus is forced to the surface because it finds the least resistance in that direc tion; but, if an aponeurosis or fascia interfere, it burrows until an exit is I found.
The role of the white corpuscles (leu cocytes) has been interpreted in various ways; Cohnheim considered them as ele ments of repair; others have attributed to them the role of scavengers. The prevailing theory at present, however, is that of Metschnikoff, who considers them able to attack and destroy invading or ganisms. The process is termed by him phagocytosis, the cells being called pha gocytes ((payo, to eat, and xtyroc, a cell).
The dead leucocytes in pus must be looked upon as the cells that have been brought up rapidly to interfere with the spread or diffusion of the products of the micro-organisms; a large number of these cells coming in contact with the poison in a concentrated form may suc cumb to its action; but before doing so they are able to deal with a certain quan tity of the poisonous material, breaking it clown and rendering it inert. Other cells are constantly being brought up to assist these, until, at length, the bacteria are completely hemmed in. They live for a short time on the dead tissues; but, being localized by the barrier of leuco cytes, they ultimately die, either from inanition or because they are poisoned by their own products. It is found very frequently on opening an abscess that no organisms can be seen, those that were originally present appearing to have undergone degenerative changes and to have been taken up by the phagocytes, or devouring cells. (Sims Woodhead.) Differential Diagnosis. — Fluctuation only indicating the presence of fluid, the presence of this sign without the other symptoms mentioned should inspire great circumspection, especially if surgical measures are to be resorted to.