196 BACTERIOLOGY 



CHAPTBE IX 



BACTBEIOLOGICAL EXAMINATION OF PUS 



Properties and composition of pus. — Pus shows an alkaline 

 reaction and possesses a high specific gravity, consequently 

 it furnishes an excellent nutrient medium for the most 

 widely differing micro-organisms, and that whether it is 

 derived from exudations or from the surface of wounds, or 

 is formed in some other inflammation of tissue. 



Furthermore, pus may be coloured, the tint being 

 greenish or brown-red, and it exhales a peculiar odour. In 

 it are found white and red blood corpuscles, blood pigment, 

 and crystals of hsematoidin, epithelial cells, drops of fat, 

 fungi, micrococci, and bacilli. 



Suppuration may also be excited by bringing certain of 

 the micro-organisms contained in pus into contact with the 

 tissues, when their vital activity will start the process. 

 Amongst these microbes is included more especially the 

 Stajjhylococcus pyogenes, which, as we have already remarked 

 in the chapter on the ' Bacteriological Analysis of Air ' (see 

 p. 110), is very widely distributed in nature. Eosenbach 

 also found the Bacillus saprogenes III (see p. 176) in pus. 



Actinomyces. — A fungus has been detected compara- 

 tively recently in almost all organs, in certain cases of 

 chronic inflammation combined with suppuration, which 

 has been named Actinomyces or ray-fungus. It had been 

 discovered by Langenbeck as long ago as 1845, but it was 



