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A GUM (LEVAN) BACTERIUM FROM A SACCHARINE 

 EXUDATE OF EUCALYPTUS STUART IAN A. 



[Bacterium eucalyjHi, n.sp.) 



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



Society. 



(Plate xii.) 



A sweet exudate from a species of Eucalyptus was upon exami- 

 nation found to contain a quantity of gum precipitable by alcohol, 

 and, as several gum-forming bacteria had been under investigation 

 in the Society's laboratory, the specimen was tested to see if the 

 gum could possibly have a microbic origin. Plates of saccharose- 

 gelatine* were infected in the usual manner, and upon these there 

 developed the dome-shaped colonies so characteristic of many 

 gum bacteria. 



The exudate was a pale straw-coloured syrup, very similar in 

 appearance and consistency to honey or golden syrup, and had 

 fragments of bark, Eucalyptus capsules, etc., scattered throughout 

 the mass. When dissolved in water and separated from woody 

 debris, a portion contained : — 



Non-reducing but hydrolysable sugarf calcu- 

 lated to saccharose ... ... ... 1*1 grm. 



Reducing sugars ... ... ... ... 2-5 ,, 



Crude gum ... ... ... ... ... 0*8 ,, 



* Saccharose 10, peptone 0*25, potassium chloride 0"5, sodium phosphate 

 0*2, gelatine 10, water to 100. Acidity to phenolphthalein 10 c.c. =0'1 c.c. 

 tenth normal acid. 



t This is probably raftinose, the sugar of Eucalyptus manna. The reducing 

 sugars probably consist of a mixture of levulose and melibiose. 



