468 BACTERIOLOGY. 



Occurrence in Man. The staphylococcus pyogenes 

 aureus is the commonest pyogenic micro-organism found 

 in man. From the fact that these micrococci are so 

 constantly present in the pus of acute abscesses, as de- 

 monstrated by Ogston, Rosenbach, Passet and others, 

 it was formerly assumed that there could be no pus- 

 formation in the absence of micro-organisms of this 

 class; but it is now well known, from the experiments, 

 that certain chemical substances, such as nitrate of 

 silver, oil of turpentine, strong liquor ammonise, etc., 

 introduced beneath the skin, give rise to pus-formation 

 quite independently of bacteria. Practically all micro- 

 organisms, moreover, have been shown by experiment to 

 produce under certain conditions the formation of pus 

 by their products when inoculated into the animal body ; 

 but, while this has been demonstrated, the extended 

 researches of bacteriologists show that few species are 

 usually concerned in the production of acute abscesses, 

 furuncles, etc., in man. Of these the two most im- 

 portant, by reason of their frequent occurrence and 

 pathogenic power, are staphylococcus pyogenes aureus 

 and streptococcus pyogenes; next to these comes the 

 staphylococcus pyogenes albus. Two or more species 

 are often found in the same abscess; thus, Passet, 

 in 33 cases of acute abscess, found staphylococcus 

 aureus and albus associated in 11, albus alone in 4, 

 albus and citreus in 2, streptococcus pyogenes alone in 

 8, albus and streptococcus in 1, and albus, citreus, and 

 streptococcus in 1. 



As the result of extended researches, however, made 

 by bacteriologists within recent years the golden staphy- 

 lococcus has been demonstrated not only in furuncles 

 and carbuncles, but also in various pustular affections 



