Lifiamation. Plogosis. Phlegmasia. 55 



reason of their presence in small numbers in the blood. It is 

 further noteworthy that those animals in which suppuration does 

 not occur readily are such as have a special power of resistance 

 to some other organic poisons. Thus the hog, which is supposed 

 to be proof against snake-bite, is also, to a large extent, proof 

 against the pus-forming bacteria. 



Pus. This is a white, or yellowish-white, creamy-looking 

 product, composed of a clear, transparent fluid, rendered opaque 

 by numerous floating pus-corpuscles. These pus-corpuscles have 

 the same size as the white globules of the blood (a-jVo^ to 3-roTr 

 inch) and are peculiar in that each shows within it three or more 

 nuclei, which become visible on the addition of a drop of water 

 or acetic acid. Each of the common embryonal cells found in 

 the inflamed tissue usually contains two nuclei, the indication of 

 the active increase by division into two, but when the supply of 

 nutriment is checked the nuclei continue to divide, while the 

 cells remain unchanged, and thus every cell comes to contain 

 several nuclei in addition to fatty granules, and constitute pus- 

 corpuscles. 



When pus is formed in a well-maintained system and tissue, 

 the outer layer of the lymph is developed ' into a fibrous sac in- 

 closing the liquid pus and constituting an abscess. In an un- 

 healthy system, or when "the inflammation depends on some 

 injurious poison, like that of erysipelas, this sac may not be 

 formed, and the pus, burrowing into and between different 

 organs, destroys the connections and substance — diffuse siippiira- 

 tion. When an abscess has formed in soft tissues its investing 

 sac shrinks as it assumes the fibrous character, and the confined 

 pus being incapable of compression, presses the membrane out- 

 ward on the side in which the surrounding tissues are most loose 

 and least resistant, hence, usually, though not always, in the 

 direction of the skin ; the soft tissues become absorbed and re- 

 moved in the track of the advancing pus ; and, finally, the latter 

 reaches a free surface and escapes. Thus, an abscess usually 

 bursts through the skin, but also, at times, through a mucous 

 membrane into the lungs, bowels, etc., or through a serous mem- 

 brane into chest, abdomen, etc. When an abscess is formed in 

 bone or dense fibrous tissues which press equally on all sides, it 

 may remain imprisoned for months and years after all inflamma- 



