102 MICRO-ORGANISMS AND FERMENTATION. 



white slimy colonies, and in liquids a thick slimy film and a 

 solid ring attached to the side of the vessel. When shaken, 

 the film separates in flecks. The liquid is rendered turbid. 

 The optimum on wort-agar is 23 C. The upper limit of 

 temperature for motile forms is about 45 C. The species 

 oxidises a large number of compounds. The vinegar produced 

 contains much aldehyde, 



Bact. ascendens, which is found in wine and wine-vinegar, 

 likewise consists principally of single cells or pairs of cells r 

 but also forms chains. On grape-sugar gelatine and grape- 

 sugar agar the colonies are surrounded by a white halo. In 

 liquids the species forms a very delicate uniform film, which 

 creeps to an extraordinary height up the sides of the vessel. 

 The film is easily broken up and forms a flocculent deposit, 

 and the liquid is rendered turbid. On wort agar the optimum 

 is 31 C. This species is only capable of oxidising a minute 

 amount of material. The vinegar produced is distinguished 

 by its odour of acetic ether. In old cultures the vinegar has 

 a very pungent smell. 



Amongst sub-species, or varieties which occur in the 

 quick vinegar process, Henneberg has isolated the 

 following : 



Bact. Schiitzenbachi, which occurs as round, oval, or longish 

 cells, often also sickle-shaped or in irregularly bent and 

 inflated forms, sometimes single and sometimes in chains. 

 On wort gelatine it forms round, clear, glistening colonies 

 with a yellowish-brown centre. On beer- gelatine the old 

 colonies have a whitish, granulated surface. The very 

 thin film that forms on liquids easily sinks to the bottom 

 as a powder. The optimum appears to lie between 25 

 and 27-5 C. 



Bact. curvum has rounded, longish, oval, or elongated cells, 

 with either rounded or pointed ends. The more or less bent 

 cells are especially characteristic ; it also forms chains. On 

 wort-gelatine the colonies are transparent and rounded, with 

 a raised edge and projecting centre, and frequently have a 

 whitish dry appearance. The film forming on liquids 

 easily falls to the bottom. The optimum lies between 25 

 and 30 C. 



