PROTEUS ZENKERI 451 



finely granular. Liquefaction is less rapid than in the case 

 of the Proteus vulgaris. 



Gelatine Tubes. — Forms a whitish expansion, surrounded 

 by a liquid circular zone, filled with moving bacilli. At the 

 end of forty-eight hours, a moist, thick, shining pellicle 

 is formed. The whole contents of the tube are liquefied in 

 two or three days. 



Agar-Agar. — A moist, shining, dirty-white expansion is 

 formed. 



Both the above protei are pathogenic to rabbits and 

 guinea-pigs. 



Proteus Zenkeri. — This is a common putrefactive organism. 

 The bacilli vary greatly in length, average about 1'5 /* long 

 by about 0*4 fi in breadth. It is aerobic and facultatively 

 anaerobic, non-motile and non-liquefying. Spore formation 

 not observed. Cultural characters : 



Gelatine Plates. — At the end of twelve hours superficial 

 colonies are seen of 2 to 3 mm. in diameter, which under 

 a low power appear laminated and of a brownish colour. 



Gelatine Streak. — A rather thick grayish-white opaque 

 layer is formed, which soon covers the entire surface of 

 the gelatine, and is easily detached from it. This species 

 is distinguished from the two preceding ones by the fact 

 that it does not liquefy gelatine or blood serum, and does 

 not give off a decided putrefactive odour when cultivated on 

 these media. 



Pathogenesis. — The above three species of protei give rise 

 to local abscesses and to symptoms of toxaemia when injected 

 into small animals. 



Proteus Zenkeri (Granular or Sewage Variety of Klein). — 

 This organism, which was discovered by Klein, and called 

 by him the granular or sewage variety of Proteus Zenkeri, is 

 a non-liquefying, non-sporing, aerobic, non-motile bacillus, 



29—2 



