AND OF EXPOSED MUCOUS MEMBRANES. 053 



Black found in the saliva of ten healthy individuals the Staphy- 

 lococcus pyogenes aureus seven times, Staphylococcus pyogenes al- 

 bus four times, and Streptococcus pyogenes three times. On the 

 other hand, Netter found Staphylococcus aureus only seven times in 

 one hundred and twenty-seven individuals examined. Miller also 

 has rarely found the pus cocci in the mouths of healthy persons. 

 Streptococcus pyogenes was not found by Vignal in his extended 

 researches. The experiments of the writer, of Vulpian, Frankel, 

 letter, Claxton, and others show that the micrococcus which in 

 1885 I named Micrococcus Pasteuri, and which is identical with the 

 " diplococcus pneumonia " of German authors, is frequently present 

 in the healthy human mouth now called Micrococcus pneumonia 

 crouposaB. Ketter examined the saliva of one hundred and sixty-five 

 healthy individuals and obtained it in fifteen per cent of the number 

 examined. 



Another pathogenic micrococcus which is frequently present in 

 the mouths of healthy persons is the Micrococcus tetragenus of Koch. 

 The following pathogenic bacteria have also been isolated and de- 

 scribed : Bacillus crassus sputigenus (Kreibohm), Bacillus salivarius 

 septicus (Biondi). The Streptococcus septo-pyaBmicus of Biondi is 

 described as having characters identical with those of the Strepto- 

 coccus pyogenes of Rosenbach. Two other pathogenic species de- 

 scribed by Biondi were each found in a single case only. Miller 

 has described the following pathogenic species isolated and studied 

 by him : Micrococcus gingiva3 pyogenes, Bacterium gingivse pyo- 

 genes, Bacillus dentalis viridans, Bacillus pulpa3 pyogenes. 



Rosenthal (1893) examined the secretions from the mouths of 

 fourteen individuals and obtained twenty-eight different bacteria; of 

 these twenty-one had been previously described. Five species be- 

 lieved to be new are described in detail by Rosenthal, viz. : Sarcina 

 viridis flavesceris, Micrococcus Reessii, Micrococcus ochraceus, Dip- 

 lococcus Hauseri, Bacterium cerasinum. 



Vignal has tested a considerable number of microorganisms, 

 obtained by him in his cultures from the healthy human mouth, with 

 reference to their peptonizing action upon various kinds of food, with 

 the idea that some of them may have an important physiological 

 function of this kind. Out of nineteen species he found ten which, 

 after a longer or shorter time, dissolved fibrin, nine which dissolved 

 gluten, ten which dissolved casein, and five which dissolved albumin ; 

 nine changed lactose into lactic acid, seven inverted cane sugar, seven 

 caused the fermentation of glucose, and seven coagulated milk. 



Sanarelli (1891) has shown that normal saliva has the power 

 of destroying the vitality of a limited number of certain patho- 

 genic bacteria, including the following species: Staphylococcus 

 pyogenes aureus, Streptococcus pyogenes, Micrococcus tetragenus 



