AND OF EXPOSED MUCOUS MEMBHANES. 651 



variety of bacteria; among others the pus cocci were frequently 

 found by both of the observers mentioned. In eighty one cases Von 

 Besser found the " diplococcus pneumonias " fourteen times, Staphy- 

 lococcus pyogenes aureus fourteen times, Streptococcus pyogenes 

 seven times, and Friedlander's bacillus twice. Twenty-eight of the 

 cases examined were convalescents in hospital; among these the 

 pathogenic species mentioned were found less frequently than in other 

 individuals. The following non-pathogenic species were isolated: 

 Micrococcus liquefaciens albus in twent}*-two cases, Micrococcus al- 

 bus in nine cases, Micrococcus cumulatus tenuis in fourteen cases, 

 Micrococcus flavus liquefaciens in three cases, Bacillus striatus albus 

 in ten cases, etc. 



Paulsen (1890) made thirty-one cultures in nutrient gelatin from 

 sixteen persons and thirty-three in nutrient agar from twenty-two 

 persons, with the following result : Eleven remained sterile, nineteen 

 showed not more than ten colonies, sixteen less than one hundred, 

 twelve more than one hundred, and in six the number was so great 

 that they could not be counted. Micrococci were more numerous 

 than bacilli ; of these a " sulphur-yellow coccus " in tetrads was found 

 in eight individuals. Various species of liquefying cocci, resem- 

 bling the pus cocci, were isolated, but the conclusion was reached 

 that none of these were identical with the staphylococci of pus, 

 which Von Besser and Wright both found in a considerable propor- 

 tion of the culture experiments made by them. 



Thomson and Hewlett (1895) have recently reported results which 

 differ to some extent from those previously reported. While they 

 found numerous bacteria in the vestibulum naris, cultures made from 

 mucus obtained from the interior of the nose usually gave a negative 

 result sixty-four out of seventy-six remained absolutely sterile, 

 while in seven there was a scanty growth only. They conclude that 

 while microorganisms are occasionally found upon the Schneider- 

 ian membrane they are not numerous and are often entirely absent; 

 and that the}* are rarely found upon the pituitary membrane. Straus 

 (1895) has examined the nasal secretions of persons associated with 

 tubercular patients for the purpose of ascertaining if the tubercle ba- 

 cillus was present. The presence of this bacillus was demonstrated, 

 by inoculation into guinea-pigs, in nine healthy individuals out of 

 twenty -nine examined ; two of these were physicians and six were 

 nurses. 



Very extended researches have been made with reference to the 

 bacteria present in the human mouth, which show that numerous 

 species are constantly present in the buccal secretions and upon the 

 surface of the moist mucous membrane. Some of these are occa- 

 sional and accidental, while others appear to have their normal habi- 



