BY R. GREIG SMITH. 



239 



present in a medium and a suitable temperature maintained, there 

 is little need to have salts or other constituents. The slime may- 

 be slightly increased by the addition of traces of a citrate or a 

 succinate, of glycerine and of tannin. The best medium for 

 enabling BacL acacice to form its slime in the laboratory should 

 contain the following constituents, and the infected medium 

 should be incubated at 17°. 



This medium is something more than a substratum for growing 

 the slime of Bad. acacice. It is a diagnostic for the slime-forming 

 bacteria. Some organisms, e.g., Bad. acacice, form a voluminous 

 slime upon it readily; others, e.g., Bad. metarabinum in its high- 

 est state of development in artificial culture, produce a tough 

 leathery growth ; w^hile others, e.g., Bac. levaniformans, refuse to 

 grow. Following is a list of the gum bacteria with which I have 

 worked : — 



Slime peoduced. 



No SLIME PRODUCED. 



Bad. acacice. 



Bad. metarabinum (dry, tough). 



Bad. sacchari. 



Bad. pararabinum . 



Bad. levaniformans. 

 Bad. eucalypti. 

 Bact. vascularum. 

 Bact. persicce. 



Gum Bacteria under investigation and not yet described. 



