36 



Structure and Classification of Micro-organisms 



A spiral organism of ribbon shape is called spiromonas, while a 

 similar oganism of spindle shape is called a spirtdina. One species 

 of spiral bacteria in whose cytoplasm sulphur granules have been 

 detected has been called ophidiomonas. 



Spiral organisms with undulating membranes are known as 

 spirochceta, but these and the similar genus treponema are now 

 regarded as more correctly placed among the protozoan organisms. 



THE fflGHER BACTERIA 



The Higher Bacteria form a group intermediate between the 

 Schizomycetes, or true bacteria, and the Hyphomycetes, or molds. 

 In the classification of Migula and Chester they include the Myco- 



Fig. 5. — Cladothrix, showing false branching. (From Hiss and Zinsser, 

 "Text-Book of Bacteriology," D. Appleton & Co., publishers.) 



bacteriacese and the Chlamydobacteriaceas. Some, like Petruschky, 

 believe them to be more closely related to the true molds than to the 

 bacteria. They are characterized by filamentous forms with real or 

 apparent branchings. The filaments are usually regularly divided 

 transversely, so as to appear as if composed of bacilli. The free 

 ends only seem to be endowed with reproductive functions, and 

 develop peculiar elements that differentiate the higher from the 

 other bacteria whose cells are all equally free and independent. 



Leptothrix. — These comprise long threads which do not branch. 

 They are not always easily separated from chains of bacilli. They 

 rarely appear to play a pathogenic r61e, though those inhabiting 

 the mouth occasionally secure a foothold upon the edges of the 

 tonsillar crypts, where they grow, with the formation of persistent 

 white patches. This form of leptothrix mycosis is chronic and diffi- 



