34° BACTERIA. 



(6) -A third curved or spiral organism is also described — somewhat l6nger 

 than the others ; it, pccurs in longer or shorter, straight or spiral filaments, 

 *tiich may brejtk up into rods and even into chains of cocci ; this origanism' 

 when cultivated in gelatine does not give rise to any liquefaction, differing 

 in this respect from either the Koch's cholera or comma bacillus or the 

 Finckler- Prior bacillus, the latter of which has also been described by Miller, 

 as occurring in the mouth. Miller maintains indeed that some of these 

 curved organisms may pass into the lower parts of the alimentary canal, 

 but that even when he took them from this position he never succeeded in- 

 making pure cultures of them ; they will not grow on any of the nutrient 

 media that have been as yet devised. 



, (7) Then, of these more important forms, is the Spirochete dentium or 

 Spirochmte denticula, which is usually found associated with the (8) Spirillum 

 sputigenum, and under similar conditions ; it consists of a long spiral thread 

 from 8 to 25/j in length, of which the spirals are irregular and of unequal 

 thickness. Very little is known of this organism, and it is quite possible 

 that the thicker spirals may represent some stage of development of the 

 preceding organism, especially as in this case it is also impossible to obtain 

 any artifici^. cultures. . As already stated, other organisms are very fre- 

 quently, though not invariably, met with. 



Vignal describes a number of bacteria and bacilli as occur- 

 ring in the mouth and amongst these certain common forms 

 that are generally recognized, such as Bacterium termo (?) 

 Bacillus iilha^ the potato bacillus, Bacillus alvse, and a number 

 of others, whilst amongst the cocci are found the Staphylo- 

 coccus pyogenes albiis, and S. pyogenes aureus, &c. Hueppe 

 describes organisms that give ris.e to the lactic acid fermenta-; 

 tion, whilst others, especially those giving rise to pigment 

 and pathogenic bacteria of various kinds, most of them well 

 recognized, have a peptonizing action, and a few appearing 

 to secrete a. true diastatic ferment may also be met with 

 in tjie mouth. i; 



. ■ Miller gives some interesting statistics as to the action of 

 the bacteria found in the mouth upon carbohydrates ; he 

 finds that of twenty-two kinds of ,ftiputh bacteria which he 

 nieritions, ."sixteen brought aboiit an acid reaction when 

 cultivated in beef extract peptone solution, four produced an 

 alkaline reaction under the ■ same conditions, whilst in the 

 case of two onlythe reaction remained neutral." Many of 

 these organisms also exert an enzyme function in a some- 

 what marked degree ; most of them Jiave the power of 

 peptonizing coagulated albumens, during whioh' they give 

 rise to the usual ultimate products — sulphuretted hydrogen, 

 animohia,' carbonic acid gas or combinations of these, peptones 

 of course also being formed. 



