THE SPIROCHETES : 



A REVIEW OF SOME BORDER-LINE ORGANISMS 

 BETWEEN ANIMALS AND PLANTS 



By H. B. FANTHAM, D.Sc. 



Assistant in the Zoological Department, University College, London 



Among the many micro-organisms now receiving attention from 

 both medical and biological investigators, few are of greater 

 interest than the Spirochaetes. They are long, wavy, thread- 

 like organisms, lying on the border-line between animals and 

 plants, and are variously regarded as Bacteria or Protozoa. 

 It is, perhaps, still difficult to settle their systematic position 

 definitely, and, indeed, it is to some extent unnecessary, for 

 Haeckel long ago gave the name Protista to the lowliest 

 organisms, whether animal or plant, the division between 

 which is not hard and fast. 



Spirochaetes are of great economic importance, for it is to 

 these organisms that the pathogenic agents of relapsing fever 

 in human beings and fowls belong, also of tick fever in man, 

 and probably of syphilis (fig. i, c). 



Spirochceta is the name given by Ehrenberg in 1833 to a 

 genus of microscopic, sinuous, thread-like forms which are 

 relatively of great length compared with their breadth (fig. 2, b). 

 The type species, S. plicatitis, was found in pond-water by 

 Ehrenberg ; and was described and figured by him in a paper 

 (4) 1 published in 1835. According to the great protistologist, 

 the late Dr. Fritz Schaudinn (10), this type species possesses 

 an undulating membrane (fig. 1, a). Strict members of the 

 genus Spirochceta, then, should possess an undulating membrane 

 or lateral extension of the outer layer (ectoplasm) of the body. 

 This membrane is an outgrowth and is wound spirally round 

 the body, forming, as it were, a spirally coiled lateral fin, 

 which is used in locomotion (figs. 2, a, b). 



1 The numbers in parentheses refer to the List of References to Literature at the 

 end of this memoir. 



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