LEUCONOSTOG 627 



with a red flocculent sediment (Bergey 1923). L.M. slightly alkaline. Carmine-red 

 streak on potato. Does not liquefy gelatin, but generally reduces nitrates. Aerobic. 

 Optimum temperature 25° C. Non-pathogenic. 



Rhodococcus cinnabareus Fliigge. — Described by Fliigge as a large, spherical. Gram- 

 positive coccus, occurring in twos, threes, and fours ; grows very slowly. On gelatin 

 after 4 days the colonies are 0-5-1-0 mm. in diameter ; at first they are brick-red, later 

 cinnabar-red in colour. In gelatin stab small white colonies are formed down the stab 

 in 4 to 5 days ; on the surface there is a large red loiob of growth ; no liquefaction. On 

 potato the growth is even slower. Optimum temperature 25° C. Does not reduce nitrates, 

 and cannot utilize ammonium salts as the sole source of nitrogen. Found in air and water. 



Rhodococcus roseofulvus Fliigge. — Described by Babes as the cause of red sweat (see 

 Fliigge 1896). The cocci are oval in shape, 1 /n long by 0-6-0-8 fi broad, and are bound 

 by gelatinous material into a reddish zoogloeal mass. In the body they surround the hairs, 

 particularly of the axilla, and impart a red coloration to the sweat. Gram-positive. 

 Grows on egg white at 37° C, forming a red pigment. Does not liquefy gelatin. Generally 

 curdles milk and causes slight peptonization. Produces acid in glycerol and mannitol. 



Rhodococcus agilis Ali-Cohen.- — Isolated by AU-Cohen (1889) from diinking water 

 and named Micrococcus agilis. Peculiar in being motile, possessing one or two flagella. 

 Occurs mostly in pairs, sometimes in short chains or in tetrads. Gram-positive ; 1 // in 

 diameter. Grows in all media at room "temperature, forming a rose-coloured pigment. 

 Liquefies gelatin slowly. Optimum temperature 25° C. Found in water. 



Leuconostoc 



Definition. — Leuconostoc. 



Spherical or ovoid cells, arranged in pairs and chains ; the cocci are surrounded 

 by a gelatinous envelope, which unites them into zoogloeal masses. Usually Gram- 

 positive, but decolorize easily. Saprophytes, usually growing in cane sugar solu- 

 tions. 



Type species is Leuconostoc mesenterioides van Tieghem. 



The first organism of this group was described by Cienkowski in 1878 as the 

 Ascococcus mesenterioides. This name was amended by van Tieghem in 1878 

 to Leuconostoc mesenterioides (see Fliigge 1896). According to Hucker and Pederson 

 (1930), to whom reference should be made for more detailed information, organisms 

 of the genus Leuconostoc are found in slimy sugar solutions, in fermenting vegetables, 

 and in milk and milk products. Morphologically, they are intermediate between 

 the streptococci and the lactobacilli. They all produce about 45 per cent. Isevo- 

 lactic acid from glucose, 20 per cent. COj, and 25 per cent, volatile products, includ- 

 ing acetic acid and ethyl alcohol. They form mannitol from fructose and sucrose, 

 and a levulan or dextran from sucrose. 



Leuconostoc mesenterioides (Cienkowski) van Tieghem. — A spherical coccus, 0-9-1 -2 /i 

 in diameter, occurring in pairs and in chains. Usually Gram-positive. The chains are 

 surrounded by a thick, tough, gelatinous coating, which is stated by von Scheibler to 

 consist of dextrin ; the aggregation of several chains within their envelopes gives rise 

 to large, oompact, gelatinous, zoogloeal masses. Develops on the surface of parsnip-root 

 and beetroot solutions in the form of thick cakes of cartilaginous consistency (Fliigge 

 1896). It likewise thrives on grape-sugar and cane-sugar solutions, provided nitrate 

 and phosphate are added. Cultivated in peptone water, or in gelatin to which lactose 

 or maltose has been added, it is morphologically similar to a streptococcus, no gelatinous 

 envelope being formed ; but if glucose or cane sugar is incorporated in the gelatin, then 

 the characteristic zoogloeal masses appear. On either of these media there appears in 

 10 to 14 days a thick whitish mass of confluent colonies, having a glassy surface, looking 



