222 GENERAL SYSTEMATIC BACTERIOLOGY 



by subsequent authors as to make identification difficult. However, 

 Bad. acidi-lactici may be regarded as a possible type species. 



Engelmann (1882, p. 94) described an organism from water as Bac- 

 terium photometricum. It was insufficiently differentiated. 



Kurth (1883, p. 97) isolated and described from the alimentary tract 

 of the domestic fowl an organism which he named Bacterium Zopfii. 

 This organism is adequately known at the present time. 



Lanzi (1883, abs. 1884, p. 786) described an organism as Bacterium 

 morhilli but not adequately. 



Luerssen (1879, p. 20) used the generic diagnosis of Cohn as did also 

 Grove (1884, p. 22). This latter author lists five colorless species 

 (including Bact. termo) and four chromogenic species (including Bact. 

 synxanthum Schroter, Bact. syncyaneum Schroter, Bact. aeruginosum 

 Schroter and Bact. violaceum (Bergonzini) Grove). The chromogenic 

 species may all be recognized. 



Van Tieghem (1884, p. 1110) defined Bacterium as containing rod- 

 shaped cells, separating as soon as formed, never in filaments, never 

 spiral. He regarded the name more as a form genus than a natural 

 genus. 



Escherich (1885) described two organisms, Bacterium coli commune 

 and Bacterium lactis aerogenes, from infant stools. The description 

 was greatly expanded the next year (1886, pp. 57 and 63) . These organ- 

 isms have been consistently known by these names to the present time. 



In 1885 Trelease described several new species of pigmented bacteria 

 under the names Bacterium candidum, Bact. luteum, Bact. aurantiacum, 

 Bact. chlorinum and Bact. incarnatum. Zukal (1885) studied the mor- 

 phology of a Bacterium tortuosum from water. 



Zopf in 1885 (p. 61) completely revised his classification. Bacterium 

 is defined as made up of those species which exist as cocci and rods, or 

 the latter only, united into filaments, spore formation lacking or un- 

 known. It will be noted that here the emphasis is changed to absence 

 of spores. Hueppe (1885) used practically the same diagnosis. Maggi 

 (1886, p. 84) listed five species of this genus. 



Fltigge (1886) outlined a classification of bacteria which has been 

 extensively followed by medical bacteriologists. His genus Bacterium 

 is defined to include cylindric forms, short, single or loosely united or in 

 amorphous slimy masses. 



Schroter (1886, p. 155) states that the genus Bacterium is not well 

 characterized and possibly should be united with the genus Bacillus 

 from which it is separated with difficulty. He accepts absence of spores 



