The Higher Bacteria 



37 



cult to treat. The leptothrix is a very difficult organism to secure 

 in culture. The attempts of Vigna)* and of Arustamoff 1 " were 

 successful, but upon the usual culture-media the organisms grew 

 very sparingly. 



Cladothrix. These also produce long thread-like filaments, but 

 they occasionally show what is described as false branching; that is, 

 branches seem to originate from the threads, but no distinct connec- 

 tion between the thread and the apparent branch obtains. None of 

 the cladothrices is known to be pathogenic. They are frequent 

 organisms of the atmospheric dust, and not infrequently appear as 

 "weeds" in culture-media. The colonies grow to about a centi- 

 meter in diameter, are usually white in color, irregularly rounded, 



Fig. 6. Streptothrix enteola. Film preparation from peptone-beef-broth 

 culture, fourteen days at 37C. X 1000. (Foulerton.) 



sharp at the edges, more or less concentric, dry and powdery (not 

 velvety) or scaly on the surface. They commonly liquefy gelatin 

 and blood- serum. 



Streptothrix. These organisms certainly branch. They also form 

 endospores. Many of them can be cultivated. Not a few are 

 found under circumstances suggesting pathogenic action. For a long 

 time there has been a disposition to regard Bacillus tuberculosis as a 

 form of Streptothrix, since old cultures show branching involution 

 forms. The old genus actinomyces is also included by a number of 

 writers among the streptothrices, so that the Actinomyces bovis of 

 Bellinger is called Streptothrix actinomyces, the Actinomyces 

 madurae, Streptothrix madurae, and the organism found by Nocard 

 in the disease known as "farcin.du bceuf," Streptothrix farcinica. 



*"Annales de physiologie," 1886. 



t"Kolle and Wassermann, "Handbuch der Pathogenen Mikroorganismen," 

 1903, IT, p. 851; Wratsch, 1889. 



