CHAPTER XIX 



STAPHYLOCOCCUS INFECTIONS 



THE staphylococcus was first observed by Pasteur in 

 1880 ; and first carefully studied in pure culture by 

 Rosenbach in 1884. As seen in colonies, the organism 

 appears orange, white, or lemon yellow, and is, there- 

 fore, divided into varieties termed respectively Staphy- 

 lococcus aureus, Staphylococcus albus, and Staphylo- 

 coccus citreus. The individual organisms are small 

 spheric bodies, which usually group themselves in 

 irregular masses. They stain well with the ordinary 

 stains, and do not decolorize when treated according 

 to Gram's method. They grow well even at room tem- 

 perature, and do not demand any special media. When 

 grown on gelatin they cause liquefaction of the medium. 



The staphylococcus is much more resistant than 

 other non-spore-bearing bacteria. Cultures may some- 

 times be heated for an hour to 140 F. without killing 

 all the organisms. Dried pus contains living staphylo- 

 cocci for weeks and even months, and they can be found 

 alive in the dust of air almost everywhere. To kill the 

 organism in pus with bichlorid of mercury, 1:1000, 

 requires an exposure of several hours. 



The most common bacterial excitants of acute ab- 

 scesses in man are the Staphylococcus and the Strep- 

 tococcus pyogenes, though, of course, other bacteria 

 may also produce abscesses. The Staphylococcus albus 



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