THE LEUCO-THIOBACTERIA 129 



or two windings, widtli of winding 6/i., sulphur globules 

 disposed in a single line. 



Habitat. — Found in various parts of Germany. 



Note. — It is doubtful whether this organism is sufficiently 

 defined from^ the above description to justify giving it a specific 

 name, 



Thiospirillum ELONGAiA. — Perfiljeff, 1923. 



Literature. — Perfiljeff, 1923 ; Bavendamm, 1924. 



Bavendamm gives the following description. Slender 

 cells with steep windings, and pointed ends. Dimensions 

 1-2 — I-5/X thick (in the middle) and 12 — 28ju long. The ends 

 are filled with volutin granules. Two polar cilia. Membrane 

 with spiral thickening. 



Habitat. — Found in fresh water overlying mud rich in 

 hydrogen sulphide, near Leningrad. 



Note on the Sulphur spirilla. — It is unfortunate that 

 practically nothing is known of the life-histories of these 

 interesting forms, and specific namics have been given almost 

 entirely from the appearance presented by the adult organisms. 



Family 4. — Thiob.a cilla ce.e. 



Free, colourless, motile or non-motile cells. Division by 

 transverse fission. The term Bacillus in Migula's classification 

 is used to designate motile, rod-shaped cells, and the term 

 Bacterium is used for similar cells that are non-motile. It is 

 doubtful, however, whether the distinction can be maintained. 

 Five species of the genus Bacterium were chosen at random, 

 and in all it was found possible to induce movement (see Ellis 

 (3)). It is, therefore, extremely probable that the motility 

 or non-motility of these organisms is conditioned by the nature 

 of the environment, and that the two terms apply to the same 

 organisms. In this work the term Bacterium is not used with 

 generic significance, and the term Bacillus is used for both the 

 motile and the non-motile rod-shaped organisms. There is 

 another reason for discarding the word Bacterium. Its proper 

 use in the English language is obviously as the singular of the 

 word Bacteria^ and it would therefore be better to restrict its 



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