NON-PATHOGENIC BACTERIA. 277 



Some of them (beggiatoa, thiothrix) contain sulphur granules. 

 Many of them occur in water. There are foims among them 

 which are found attached to some object by one end of the fila- 

 ment '(thiothrix) . Some of them (actinomyces or streptothrix) 

 ha^'e branching filaments, which are rarely seen among the 

 lower bacteria (see page 119). Often one end of the filament 

 becomes specialized for the purposes of reproduction. The 

 fungus of actinomycosis is the best known of this group. 

 There are many other members, however, both pathogenic 

 and non-pathogenic. Most of them require still further study. 

 The tubercle bacillus and other acid-proof bacilli which re- 

 semble it have some points of resemblance with actinomyces 

 (see B. tuberculosis, Part IV.). 



Leptothric Buccalis. — ^Found in the mouth cavity. This 

 name has been applied to large, twisted, thread-like organisms, 

 in which segments can be demonstrated with difficulty or not 

 at all. Apparently, different organisms have been described 

 under this name. Vignal claims to have cultivated a Lepto- 

 thrix buccalis. Miller recognizes two principal species, neither 

 of which could be cultivated — Leptothrix innominata, which 

 shows no transverse divisions, and which is stained faintly 

 yellow by iodine; and Bacillus buccalis maximus, in which the 

 transverse divisions are distinct, and which is stained brown- 

 ish-violet by iodine. Miller's Leptothrix maxima buccalis is 

 similar to the last except in lacking the iodine reaction. 



A variety of leptothrix, or a nearly related organism, appears 

 to be the most frequent cause of the form of gangrenous in- 

 flammation of the mouth and genitals called noma. It stains 

 faintly by Gram's method. It does not grow on ordinary 

 media.* Another organism of this group has been described 

 which is pathogenic to a number of domestic animals. f 



*BIumerandMacFarlane. American Journal Medical Sciences. November, 

 1901. 



fit has also been called "necrosis bacillus," and "Streptothrix cuniculi." 

 Pearce. University of Pennsylvania Medical Bulletin. November, 1902. 



