142 BACTERIOLOGICAL EXAMINATION OF WATER. 



Gelatine-streak. After two days a narrow, prominent line of 

 growth of a pale pink tint, which eventually attains a width of 

 1*5 to 2 mm., and a bright pink colour. Liquefaction occurs 

 after fourteen to sixteen days. 



Gelatine-stab. Definite growth in three days, almost entirely 

 confined to the surface ; in the depth of the gelatine little or 

 no development occurs. A flat layer, 4 mm. in diameter and 

 of a light pink colour, is present on the surface at the end of a 

 week. Liquefaction is extremely tardy, but some depression of 

 the surface occurs after a fortnight, and distinct liquefaction 

 begins in sixteen days. 



Agar-ugar. Streak -cultures at 20 C. show distinct growth 

 in two days, semi-transparent and barely pink. At the end of 

 a week the growth is opaque and of a bright pink colour. At 

 37 C. no growth occurs. 



Potato. A thick layer of a brilliant deep pink colour, which 

 eventually covers the whole surface. 



Broth. The fluid gradually becomes turbid, and after a week 

 there is a light pink sediment at the bottom of the tube. 



Temperature. Grows well at 20 to 22 C. No growth on 

 any medium at 37 C. 



Spore-formation. Not o bserved . 



Gas-production. Not observed. 



Need of oxygen. Growth very scanty away from the 

 surface. 



Pigment-production. Produces a bright pink pigment, readily 

 soluble in alcohol, only slightly so in water. 



Relations. Appears most closely related to Micrococcus 

 agilis and Micrococcus roseus, but differs from the former in the 

 absence of motility and the lighter pink colour of the cultures, 

 and from the latter in the absence of any growth at 37 C. 



Bacillus Cloacae Fluorescens. 



Source. Found in Homerton sewage and sewage from St. 

 Bartholomew's Hospital. 



Form and Arrangement. Motile rods, on an average twice as 

 long as broad. Breadth, 0'6 to 0'75 ju ; length, 1 to 2 u. The 

 rods are sometimes attached in chains. It is actively motile. 

 It is unable to grow at 37 C. No spore formation. 



