8o SULPHUR BACTERIA 



considerably impaired. Of the fourteen genera the generic 

 names Lamprocystis, Thio splicer ion, and Thiopolycoccus have 

 been discontinued for reasons given later. The remaining 

 eleven genera are retained with modifications. Since the 

 publication of Winogradsky's system a comparatively large 

 number of new genera have been added. 



Both the defects of Winogradsky's scheme and the discovery 

 of new genera which do not readily fit into his scheme, make it 

 necessary to modify the bases of grouping used by him. 



This classification is, however, one of great importance 

 since it has formed the pivot about which have turned the 

 majority of subsequent systems. The genera established by 

 Winogradsky have been incorporated into the general schemes 

 of classifications of bacteria. They appear with a few modifica- 

 tions in the elaborate classifications of De Toni and Trevisan 

 (1889), Hansgirg (1888), Cornil-Babes (1890), Migula (1890 

 and 1894), Ludwig (1892), Sternberg (1892), Fischer (1895), 

 Lehmann and Neumann (1896), Chester (1897), Kendall 

 (1902), and Molisch (1907). During the period 1888-1907 

 there were no investigations to determine the validity of 

 the features selected by Winogradsky for the grouping of 

 the sulphur bacteria. Their diagnostic value had not been 

 challenged, and in all, the facts of pleomorphism were either 

 unknown, or if known, disregarded. The most noteworthy 

 contribution to our knowledge of the sulphur bacteria dur- 

 ing this period was Molisch's Die Purpurhakterien, and in 

 the system established by him notable changes were intro- 

 duced. 



During the period 1888- 1907 a new genus of colourless 

 sulphur bacteria was discovered by Hinze (1903), and 

 named Thiophysa voliitans. No consideration, however, was 

 given to this organism by Molisch because this writer dealt 

 only with the coloured sulphur bacteria. 



Molisch's Classification of the Sulphur Bacteria. 

 Order RJiodohacteria. 



Bacteria coloured red, rose, violet, or carmine, by the 

 presence of bacteriopurpurin. 



