594 THE LIVEB. 



enlarge, and as they do so they approach the surface of the liver. Here 

 the contents of the abscess may be discharged into the peritoneal cavity. 

 More frequently, however, as they approach the surface, a localized 

 adhesive peritonitis ensues, so that the liver becomes bound to adjacent 

 parts, and thus the abscess may open into the pleural cavity, or, owing 

 to a secondary pleurisy with adhesions, into the lung tissue. They may 

 open into the pericardium. They may open externally through the ab- 

 dominal wall ; into the stomach, duodenum, colon, or pelvis of the right 

 kidney ; into the hepatic veins, portal vein, vena cava, or gall bladder 

 or gall ducts. 



The early stages in the formation of large abscesses of the liver are 

 but little known. It is probable, however, that in many cases they are 

 the result of the confluence of smaller abscesses (Fig. 373). Their con- 

 tents, usually bad-smelling, may be thick and yellow like ordinary pus, 

 but more commonly they are thin, reddish -brown, or greenish in color 

 from admixture with the pus of blood, gall pigment, and broken-down 

 liver tissue. Microscopical examination shows the contents to consist of 

 fluid with pus cells, more or less degenerated blood, degenerated liver 

 cells, fragments of blood-vessels, and pigment granules and crystals. 

 The walls of the abscess are usually ragged, shreds of necrotic liver tissue 

 hanging from the sides. Microscopical examination of the liver tissue 

 near the abscess shows infiltration with pus, flattening of the liver cells 

 from pressure, cloudy swelling, and necrosis of those lying along the 

 cavity. ' 



The amoebic abscesses are usually free from bacteria. Other ab- 

 scesses may contain the Bacillus coli communis, or the Streptococcus 

 pyogenes or Staphylococcus pyogenes. 



Not infrequently, however, especially in old abscesses, examination 

 both morphological and cultural fails to reveal the presence of micro- 

 organisms. 



After the discharge of the contents of the abscess or without this, if 

 it be not very large, granulation tissue may form in the wall of the cav- 

 ity and a fibrous capsule be produced, enclosing the contents, which be- 

 come thickened and often calcareous, and in this condition may remain 

 for a long time. Or the connective-tissue walls may approach one an- 

 other and join, forming a fibrous cicatrix at the seat of the abscess. 



Small multiple metastatic abscesses are not infrequent in pyaemia. In 

 these abscesses we can readily study the various stages of formation. 

 Suppurative processes in any part of the body in the head, upper and 

 lower extremities, etc. may act as distributing centres for micro-organ- 

 isms. 3 These, entering the circulation, may pass the heart and pulmo- 

 nary capillaries, with or without inducing lesions in the lungs, and, lodg- 

 ing in the vessels of the liver, induce circumscribed necrosis of the liver 

 tissue (see Fig. 41, page 113) and suppurative inflammation. Under 



1 See for a study of tropical abscess of the liver Howard and Hooter, Am. Jour. 

 Med. Sciences, vol. cxiv., pp. 150, 263, 1897, bibliography. 



2 Kruse and Pasquale, Zeitschr. f. Hygiene u. Infkr., Bd. xvi., p. 1, 1894. 



