394 DESCRIPTION OF SOME SPECIES OF MILK BACTERIA 



Biology : cultural characters — Milk 

 becomes gelatinous and very 

 viscous. 



Bouillon — Formation of white 

 flocons composed of chains of 

 8 to lo M in length, the elements 

 of which are shorter than those 

 observed in milk. No capsule 

 formation in bouillon. In solutions 

 containing sugar, the elements are 

 shorter. A slimy veil appears on 

 the surface of the liquid. 



In milk, and in solutions contain- 

 ing sugar or glycerine, the organism 

 sets up an active fermentation, with 

 disengagement of carbonic acid 

 and hydrogen, and (in the case of 

 milk only) small quantities of sul- 

 phuretted hydrogen. There is pro- 

 duction of ethylic alcohol and a 

 little acetic acid. In a solution of 

 lactate of lime, lactic acid is ob- 

 tained, but no alcohol. 

 Non-pathogenic. 



BACILLUS AIRBUS (Adametz). 



Source ana habitat — Isolated from 

 water, and found in milk. 



Morphology — Slender bacilli, straight 

 or slightly bent. 1-5 m to 4 a long 

 by 0-5 M broad. The majority lie 

 parallel to one another in groups ; 

 sometimes occur in long threads. 



Staining reaction — Ordinary aniline 

 stains. 



Motility — Feebly motile. 



Spore formation — None. 



Biology : cultural characters {includ- 

 ing biochemical features). 



Gelatine plates — The colonies de- 

 velop slowly, and are of various 

 shapes. After 8 days the larger 

 number only appear as small white 

 dots, which, however, become later 

 of a bright yellow colour, and finally 

 of a chrome yellow tint. No 

 liquefaction of gelatine. 

 Potato — An irregular, dark brown- 



yellow growth, becoming reddish- 

 brown in old cultures. 

 Non-pathogenic. 



BACILLUS, No. 14 (Adametz). 

 Source and habitat — Milk. 

 Morphology — Straight bacillus ; i to 

 4 jx long by I to 1-2 /x broad. Some- 

 times in threads. 

 Staining reaction — Ordinary aniline 



dyes. 

 Motility — N on -mot ile. 

 Spore fortnation — Oval spores are 



present. 

 Biology : cultural characters {includ- 

 ing biochem.ical features). 



Gelatine plates — Slimy mem- 

 brane ; rapidly liquefying the 

 medium. Colonies with sinuous 

 margins, granular and grey. 



Agar plates — Produces a thickly 

 folded, dirty-white skin, later be- 

 coming reddish -yellow in colour. 



Milk — At 37° C. a flaky pre- 

 cipitation occurs, with alkaline re- 

 action and peptonisation. 

 Non-pathogenic. 



BACILLUS, No. 15 (Adametz). 



Source and habitat — Milk. 



Morphology — Straight rod ; involution 

 forms occur ; 3-5 to 5 ^ long by 

 1-2 to 1-4 M broad. Sometimes in 

 threads. 



Staining reaction — Ordinary aniline 

 stains. 



Motility — Non-motile. 



Spore formation — Oval spores are 

 present. 



Biology : cultural characters {irwlud- 

 ing biochemical features). 



Gelatine plates and tubes — 

 Colonies granular, showing in the 

 middle a dark grey cloudy mass, 

 but having a clear grey margin. 

 Stab-cultures are rapidly liquefied, 

 with slight surface membrane. Old 



