2OC BACTERIOLOGY. 



in threads and colonies. They are actively motile. 

 They convert milk sugar into lactic acid ; Bacterium 

 lactis has also been described * as consisting of 

 cocci, short rods, long rods, filaments, and sac- 

 charomycetoid forms (involution-forms). The cocci 

 are about "5 p in diam., in pairs or chains, and 

 threads 1*25 p in diam. The bacteria readily 

 appear in milk, and produce the lactic acid 

 fermentation. 



Bacterium litoreum, Warming. Cells ellip- 

 soidal 2 6 /x long, i' 2 2 '4 JIG wide, occur singly 

 in sea water, never as chains or zooglcea. 



Bacterium fusiforme, Warming. Cells spindle- 

 shaped, with pointed ends, 2-5 //, long and "5 *8 //, 

 thick. Observed as a spongy layer on the surface 

 of sea water. 



Bacterium navicula, Reinke and Berthold. 

 Cells spindle-form or ellipsoidal, including motile 

 and non-motile forms. They have one or more 

 dark spots, which may be coloured blue by iodine. 

 They have been observed in rotting potatoes. 



Bacterium aeruginosum, Schroter Cells re- 

 sembling Bacterium termo. Cultivated in nutrient gela- 

 tine they liquefy the medium, and give it an iridescent 

 green colour by reflected light, and a deep orange by 

 transmitted light (Plate V., Fig. 3). On nutrient agar- 

 agar they form a white layer, and colour the medium 

 a pea-green. They are found in green-blue pus. 



Bacterium violaceum, Bergonzini. Cells 



* Lister, Quart. Jour. Micr. Sci. 1873. 



