GENERAL SYSTEMATIC BACTERIOLOGY 155 



oxalate), but no bacteriopurpurin." The family is recognized by 

 Bergey et at. (1923, p. 410) in this sense. 



The generic type is AchromaUum oxaliferum Schewiakoff (1893, p. 1). 



Achromatium. A genus of schizophytes proposed by Schewiakoff 

 (1893, p. 1) and tentatively placed by him with the bacteria. 



The species described, Achromatium oxalijerum, was found in river 

 slime, by R. Lauterbom, in considerable numbers. In form the organ- 

 ism varies from nearly spherical in newly divided cells to ellipsoidal. 

 In size the organism is larger than any other form previously described 

 among bacteria; cells about to divide are 15 to 43 /x in length, diameter 

 9 to 22 fx. Occasional!}' longer cells are found. The cells are closely 

 packed with large granules which were at first interpreted as com- 

 posed of sulfur. The use of various solvents and microchemical tests 

 indicated them to be, however, of calcium oxalate. When the granules 

 are dissolved the cell is found to contain protoplasm of a coarse alveolar 

 structure. The cells are motile, but flagella were not demonstrated. 

 Cell division is described as the result of constriction, as among flagel- 

 lates, rather than by the fission characteristic of most bacteria. 



Mig-ula (1900, p. 1038) tentatively added Achromatium Mulleri 

 (Warming) IVIigula to this genus. The organism was originally de- 

 scribed by Warming (1876) as Manas Mulleri. The descriptions make 

 it probable that this organism is misplaced in Achromatium, and belongs 

 with the sulfur forms. Migula gives the following description of the 

 genus. 



Zellen gross, eiformig cylindrisch mit grobkornigem Inhalt, der jedoch nicht 

 aus Schwefel, sondern aus Oxalsaure und einem Calciumsalz besteht. Bewegung 

 vorhanden, doch ist eine Geissel als Bewegungsorgan nicht nachgewiesen. 

 Teilung von der Bakterien abweichend, durch Einschniirung, wie bei den Flagel- 

 leten. 



Achromatium oxaliferum Schewiakoff was subsequently described 

 independently by Frenzel (1897, p. 801) as Modderula hartwigi (from 

 the name "JModder" given by North German fishermen to the slimy 

 river bottoms). Lauterbom (1898, p. 95) called attention to the 

 previous description of Achromatium, and agreed with Schewiakoff in 

 placing the organism with the bacteria. Frenzel found this form to 

 vary from 12 to oOju in length. He was able to find no adequate ex- 

 planation of the motility. The cell membrane he describes as firm, 

 almost doubly contoured, clear, colorless and structureless. He in- 

 terpreted the granules contained within the cell as sulfur. The organ- 

 ism was not cultivated in artificial media, although it continued to 



