Inflammation. Phlogosis. Phlegmasia. 55 



fully resist them, though they are constantly present in surround- 

 ing air and on objects, but in this as in all other cases of bacterial 

 infection, so soon as the tissue is injured, inflamed and lowered 

 in its power of vital resistance, the pyogenic bacteria assail it suc- 

 cessfully. Hence, too, the more abundant exudations of lymph, 

 the centres of which are farthest removed from the healthy tissues 

 and from nourishment, are the most prone to suppuration. That 

 the germs can make their way to such deep-seated exudations in 

 the substance of solid tissues is to be accounted for by their grad- 

 ual advance through the inflamed and weakened structures from 

 the adjacent skin or mucous membrane, or in some instances by 

 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 (^jV^ to -ginnr 

 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 suppura- 

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

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



