GENERAL SYSTEMATIC BACTERIOLOGY 447 



designation for the red cocci. In their later pubhcation (1908, p. 261) 

 they give the following diagnosis: 



Saprophytes. Cells in groups or regular packets. Generally decolorize by 

 Gram. Growth on agar abundant, with formation of a red pigment. Dextrose 

 broth slightly acid, lactose broth neutral. Gelatin rarely liquefied. Nitrates 

 generally reduced to nitrites, but not to ammonia. 



They recognize two species only, Rhodococcus roseus (Fliigge) Win- 

 slow and Rh. fulvus (Cohn) Winslow. It is apparent that this de- 

 scription may well be regarded simply as an emendation of that of 

 Zopf. 



Rhodococcus was independently introduced as a bacterial genus by 

 Molisch (1907, p. 20). The only species described is named Rhodo- 

 coccus capulatus Molisch. This organism is described as belonging 

 with the Athiorhodaceae , that group of the sulphur bacteria which 

 contain bacterio-purpurin, but not free sulphur granules. This generic 

 name is a homonym of Rhodococcus Zopf. This genus is recognized 

 by Orla-Jensen (1909, p. 334) as the seventh in the family Rhodobac- 

 teriaceae as a synonym of Thiopcdia. In this sense the name is invalid. 



Meyer (1912, p. 4) included Rhodococcus as a section of the genus 

 Streptococcus with the description "Alle durch Bacteriopurpurin ge- 

 farbten Streptococcusarten." He also includes a section by the same 

 name under Micrococcus with the description "Mit Schwefelkornchen." 



Buchanan (1915, p. 12) discussed the synonymy and relationships 

 of the genus. 



Buchanan (1917, p. 614) included this genus as the second of the 

 tribe Micrococceae with the description: 



Saprophytes. Cells in groups or regular packets. Usually Gram-negative. 

 Abundant growth with red pigment on surface of culture media. Slight acid 

 from dextrose, none from lactose. Gelatin rarely liquefied. Nitrate usually 

 reduced to nitrites, but not to ammonia. 



The type species is probably Rhodococcus roseus (Fliigge) Winslow. 



This genus was also recognized by Winslow et al. (Committee Soc. 

 Am. Bact., 1917, p. 560 and 1920, p. 208) with the designation of the 

 type species as Rhodococcus rhodochrous Zopf. Castellani and Chal- 

 mers (1919, p. 931) state Rhodococcus roseus (Fliigge) emendavit 

 Dyar (1895) to be the type. Bergey et al. (1923, p. 75) follow the 

 Committee. 



It would appear that Rhodococcus Zopf, is a valid name to apply 

 to the red cocci as a generic designation if they are to be grouped 

 separately, and that the type is Rhodococcus rhodochrous Zopf. 



