616 SELMAN A. WAKSMAN 



3. By the interaction of the two organisms, sulfur can be 

 oxidized at reactions ranging from pH = 9.8 to 1.0. 



TAXONOMIC POSITION OF THE COLORLESS SULFUR OXIDIZING 



ORGANISMS NOT ACCUMULATING SULFUR WITHIN 



THEIR CELLS 



The colorless organisms oxidizing sulfur and sulfur compounds 

 and not accumulating sulfur within their cells have been classified 

 by Beijerinck (1904) under the genus ThiobaciUus. Orla- 

 Jensen (1909) properly indicated the relationships of these organ- 

 isms both in their morphology and physiology to the nitrifying 

 bacteria, methane, hydrogen and other autotrophic organisms, 

 and suggested the generic name Sulfomonas in place of Thio- 

 baciUus. In view of the fact that the Committee on Characteri- 

 zation and Classification of the S. A. B. (Winslow et al.,1920) has 

 adapted several of the new generic names suggested by Orla- 

 Jensen for the members of the Nitrobactereae, the generic name 

 Sulfomonas should be used rather than that of ThiobaciUus, and 

 this genus of sulfur oxidizing bacteria should be classified with 

 the Nitrobactereae. This genus will now consists of three species : 



Sulfomonas thioparus (syn. ThiobaciUus thioparus Beijerinck, 

 Orla-Jensen 1909, p. 314). 



Sulfomonas denitrijicans {sya. Thiohadllus denitrijicans Beije- 

 rinck, Orla-Jensen 1909, p. 314). 



Sulfomonas thiooxidans (syn. ThiobaciUus thiooxidans, Waks- 

 man and Joffe). 



REFERENCES 



Beijerinck, M. W. 1904 Centralbl. f. Bakt., 11 Abt., 11, 593. 

 Gehring, A. 1915 Centralbl. f. Bakt., 2 Abt., 42, 402. 

 Orla-Jensen. 1909 Centralbl. f. Bakt., II Abt., 22, 305-346. 

 Waksman, S. A. 1922 a Soil. Sci., 13,329. 

 Waksman, S. A. 1922 b Jour. Bact, 7, 605. 

 Waksman, S. A. 1922 c Jour. Agr. Research (to be published). 

 Waksman, S. A., and Joffe, J. S. 1921 Jour. Biol. Chem., 50, 35-45. 

 Waksman, S. A., and Joffe, J. S. 1922 Jour. Bact., 7, 239-256. 

 Winslow, C.-E. A., et al. 1920 Jour. Bact., 5, 191-230. 



