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A YAKIABLE GALACTAN BACTERIUM 



{Bacillus Atherstonei, n.siD.) 



By R. Greig Smith, D.Sc, Macleay Bacteriologist to the 



Society. 



During an investigation connected with the bacteria occurring 

 in Strychnos Atherstonei, Harv., a slime bacterium was isolated 

 which grew upon plates of gelatine media as colonies of a loose, 

 almost powdery, consistency. They lay loosely upon the surface 

 of the medium and broke up into fragments when touched with 

 the needle. This behaviour was suggestive of a very insoluble 

 gum being formed by the bacterium, probably of a kind that 

 had not been credited to bacterial activity. On this account a 

 pure culture of the organism was prepared by repeated culture 

 in glucose-gelatine plates, and experiments were made to obtain 

 and identify the gum. 



The repeated purification by plate culture is necessary with 

 most bacteria, but especially is this the case with bacteria which 

 form zoogloea masses which do not liberate individual bacteria 

 upon being shaken up with the molten medium. During the 

 purification, the bacteria were grown in nutrient bouillon in 

 which little slime is formed and in which most of the cells are 

 isolated. The pure culture was infected into a saccharose- 

 peptone-fluid medium, and in the course of time this became 

 ropy. 



The bacteria could therefore produce slime from saccharose. 

 The next question was from what other sugars or carbohydrates 

 could the slime be formed? To test this point a peptone fluid 

 was prepared and put into tubes. To these were added small 

 quantities (from 1-2%) of different sugars, etc., and after a week's 

 incubation at 22° the tubes were examined. The casual examina- 



