CHAPTEK XXXIII. 



SPIRILLA PATHOGENIC VIBRIONES SPIROCHETE THE VIB- 



RIONES OF CHICKEN SEPTICEMIA AND OF ASIATIC 



CHOLERA SPIROCHETE IN MAN, OTHER 



MAMMALS AND BIRDS. 



The Systematic Classification of Spiral Bacteria. The spiral bacteria 

 may be divided into two groups. One comprises curved, rod-like 

 organisms shaped very much like a comma. They form a real spiral 

 only when a number adhere together. The other group is composed 

 of organisms which are true spirals, their bodies representing wavy 

 filaments which may best be likened to corkscrews or winding 

 stairways. Members of the first group are designated as Vibrio (pi. 

 vibriones) ; members of the second as spirillum (pi. spirilla) or spiro- 

 cheta (pi. spirochete). The term spirillum, however, is not used in a 

 very strict manner and the comma-shaped organism of Asiatic cholera 

 is known both as the vibrio and the spirillum of Asiatic cholera, while 

 in accord with strict nomenclature it should be known as a vibrio 

 exclusively. The organisms of the type of vibrio or spirillum are 

 generally very lively motile. The motility of vibriones does not differ 

 much from that of lively motile bacilli, but the motion of the spiro- 

 chete is peculiar and characteristic. It consists in a rotation around 

 their long axis, forward and backward like a spiral spring released 

 from compression, and a bending motion of the whole body. The 

 vibriones generally possess a single flagellum at one end, but flagella at 

 both ends or multiple flagella at one or both ends are also encountered. 

 Spirilla may have one flagellum at one end, one at either end, several 

 flagella at one end, or flagella surrounding the entire body. There 

 has never been any doubt in regard to the classification of the vibriones 

 among the bacteria, i. e., among the vegetable microorganisms. 

 Recently however, it has been claimed, particularly by Schaudin and 

 others, that the spirochete are protozoa and near relatives of the 

 trvpanosomes, if not indeed themselves true flagellata of this type. 

 The question will be considered fully at the end of this chapter. Most 

 vibriones are harmless saprophytes, but two species at least possess 

 very pathogenic properties. 



VIBRIONES. 



Vibrio Metchnikovi, or Spirillum of Metchnikoff . In the investigation 

 in 1887 of an epizootic among chickens in Odessa, Gamaleia dis- 



