MICROORGANISMS OP THE DIGESTIVE TRACT 497 



weeks, was able to isolate more than a hundred different kinds of bac- 

 teria from the mouth. Many of these are doubtless only transient 

 residents, having gained entrance with food, water or air. 



Among the almpst constant inhabitants of the mouth may be 

 mentioned the streptococci, both the variety which produces a green 

 color on bloodagar, the Strept. salivarius or Strept. viridans, aAd the 

 hemolytic variety, Strept. hamolyticus; the M. pyogenes var. aureus and 

 albus; the lodococcus magnus and lodococcus parvus of Miller, which 

 may be cultivated upon a sugar-starch gelatin-agar medium and are 

 stained blue by iodine; two or three species of spirilla, described by 

 Miller, which may be cultivated with some diflciculty upon ordinary 

 nutrient agar; B. fusiformis of Vincent, which may be cultivated as a 

 strict anaerobe in media containing blood serum or ascitic fluid; B. 

 maximus (buccalis) of Miller, a bacillus forming threads 0.5 to 1.5/* 

 wide and 20/* or more in length, cultivable upon maltose agar or 

 potato gelatin; Leptothrix buccalis, a slender unbranched .filament, 

 which may be brought to development on ordinary media, with some 

 difficulty. 



Even more definitely characteristic mouth bacteria are those 

 which are found in every human mouth (except in very young children) 

 and which are not cultivable in artificial media at all or only under 

 special artificial conditions never met with in nature. Among these 

 forms may be mentioned the lodococcus vaginatus, an encapsulated 

 organism. which may be stained blue by Lugol's solution acidified by 

 addition of lactic acid; the Sp. sputigenum, which is found especially at 

 the inflamed margin of the gums; the Spirochceta buccalis, Spirochata 

 media, Spirochceta microdentium and macrodentium, organisms which 

 are found in the mucus about the teeth, but are especially numerous 

 on denuded areas or in abscess cavities of the gums or in carious teeth. 

 The spirochetes of the mouth have been successfully cultivated by 

 anaerobic methods in serum and in ascitic fluid by several investigators, 

 notably by Noguchi.* 



The amoeba of the mouth, Entamceba {Endamceba) buccalis, may be 

 found in nearly every individual in the deposits between the teeth and 

 especially in carious teeth. The cell is 6 to 3 2/* in diameter, actively 

 motile, with few lobose pseudospodia. The nucleus of the living amoeba 

 is visible. Its food apparently consists of bacteria and the bodies of 



* Noguchi, Joum, Exp. Med., 1912, XV, 81. 

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