28 ] The Classification of Lower Organisms 



cells occur in swarms imbedded in slime; the entire mass moves concertedly, and is 

 eventually converted into macroscopically visible fruiting bodies. 



The group was first recognized by Thaxter. He took note that the fruiting bodies 

 of Chondromyces had already been described by Berkeley and Curtis as those of a 

 gasteromycete, and learned subsequently that Polyangium Link, also described as 

 of the puffball group, is an older name for his Myxobacter. The swarms of cells live 

 in air on damp substrata (commonly the feces of various kinds of animals), moving 

 across them and digesting and absorbing food as they proceed. Labratory culture is 

 fairly easy. As a reaction, apparently, to exhaustion of the available food, the cells 

 change into chlamydospores; the masses of spores held together by dried slime are 

 called cysts. These may be borne on simple or branched stalks built up from the 

 slime as a preliminary to the formation of the cysts and spores. The group is of 

 essentially no economic importance. 



The accepted classification is that of Jahn (1924); to the four families which he 

 recognized, one more has been prefixed for the accommodation of the genus 

 Cytophaga. 



family 1. Cytophagacea [Cytophagacae] Stanier 1940. The chlamydospores 

 formed sporadically by individual cells, not in cysts. Cytophaga Hutchinsonii Wino- 

 gradsky [Spirochaeta cytophaga Hutchinson and Clayton) is one of several species 

 discovered as active fermenters of cellulose. The slenderly spindle-shaped cells are 

 sluggishly motile, and produce ellipsoid chlamydospores resembling yeasts. 



Family 2. Archangiacea [Archangiacae] Jahn op. cit. 66. Spores elongate in irregu- 

 larly extensive masses, not in cysts. Archangium, Stelangium. 



Family 3. Sorangiacea [Sorangiaceae] Jahn op. cit. 73. Spores elongate, the 

 cysts angular, in masses, not stalked. Sorangium. 



Family 4. Myxobacteriacea [Myxobacteriaceae] (Thaxter) E. F. Smith 1905. 

 Family Polyangiaceac Jahn op. cit. 75. Spores elongate, in distinct rounded cysts, 

 clustered or solitary, sessile or borne on simple or branched stalks. Polyangium 

 Link 1795 [Myxobacter Thaxter 1892), Stelangium, Melitangium, Podangium, 

 Chondromyces. 



Family 5. Myxococcacea [Myxococcaceae] Jahn op. cit. 83. Spores spherical; 

 cysts indefinite or definite. Myxococcus, Chondrococcus, Angiococcus. 



Order 2. Spirochaetalea [Spirochaetales] Buchanan in Jour. Bact. 2: 163 (1917). 



Cells solitary, spiral in shape, actively motile. 



The first known species of this group was Spirochaeta plicatilis, observed in foul 

 waters by Ehrenberg (1838). The next was the species now known as Borrelia recur- 

 rentis (Lebert) Bergey et al., observed in the blood of relapsing fever patients by 

 Obermeier, 1873. 



During the last years of the nineteenth century, many attempts to identify the 

 agent of syphilis by standard bacteriological methods were unsuccessful. The German 

 government directed Schaudinn and Hoff'mann to continue this work. Fritz Schau- 

 dinn, 1871-1906 (Stokes, 1931), had attained distinction as a student of pathogenic 

 protozoa. Within a few weeks, by the microscopic examination of lesions, he attained 

 success where the bacteriologists had failed, and discovered Treponema pallidum 

 (Schaudinn and Hoffmann, 1905). 



Spirochaets were first cultivated by Noguchi; few others have been successful in 

 this difficult practice. It requires a medium of aseptic, not sterilized, animal ma- 

 terial, under more or less anaerobic conditions. Each species requires its peculiar 

 variant of the conditions, to which it is quite sensitive. 



