244 BACTERIOLOGY 



consisting of little masses from the size of a millet seed to 

 that of a lentil strung together in chains. According to 

 Klemperer, guinea-pigs into whose veins a pure culture ha& 

 been injected perish within from twenty-four to forty-eight 

 hours. 



Other bacteria of the mouth. Besides these, Yignal found 

 in the cavity of the mouth a considerable number of other 

 micro-organisms, such as the Staphylococcus pyogenes albus 

 and aureus, Bacillus subtilis, Bacillus mesentericus , and a 

 number of chromogenic bacteria, especially those producing 

 yellow, green, red, and brown pigment. Vignal and Biondi 

 have also found the Diplococcus pneumonice almost con- 

 stantly in the cavity of the mouth and the saliva. Rosen- 

 bach found Bacillus saprogenes I. in white plugs (see 

 p. 175). 



The Tympanum 



Micro-organisms of the tympanum. We subjoin the 

 examination of the cavum tympani to that of the mouth, 

 taking the view of Urbantschitsch that it is a diverticulum 

 from the latter. 



Netter found the Streptococcus pyogenes in diseased con- 

 ditions of the middle ear, as well as Staphylococcus pyogenes 

 and the Pneumococcus, but he encountered them not only 

 in middle-ear inflammations in adults, but also in the 

 middle ears of new-born infants. Gradenigo and Penzo 

 very often found the Micrococcus cereus albus and Bacillus 

 lactis aerogenes, and further the Micrococcus subflavus, 

 Micrococcus candicans, Micrococcus flavus tardigradus, Micro- 

 coccus urece liquefaciens, Diplococcus lacteus faviformis, 

 Bacillus fluorescens, &c. ; so that these observers could 

 find no pathogenic micro-organisms normally present in 

 the middle ear of new-born infants and those at the breast. 

 In acute otitis media, Kanthack found chiefly the Diplo- 



