A Sugar Bacterium. 



71 



Tubes of raw beetroot, infected with the gelatinous bacterial clumps, 

 showed evident sinking into the tissues in twenty-four to forty-eight 

 hours at 18°, 25°, and 31°, and in six days the depressed area showed 

 collapsed and browned cells under the microscope. A curious white 

 zone surrounded the discoloured patches. The impression gained was 

 that the bacterium draws out the sugary sap and thrives on it : no 

 proof of direct entry into the cell walls could be obtained.* 



Cooked, i.e., sterilised, beet gave a mere wet patch at first, but in a 

 week raised gelatinous lumps of the typical kind were formed. 



Here, then, we appeared to have proof that it is really the cane sugar 

 which decides the success or otherwise of the cultiues of this gelatinous 

 bacterium, and we entered on what proved to be a very long series of 

 trials with various kinds of sugars to decide this. 



Trials with Sugars. 



A series of preliminary experiments in which cane-sugar, glucose, 

 and milk-sugar were employed, made up in various ways, soon showed 

 that this bacterium grows far better in cane-sugar than in the others, 

 and better in solutions made up with yeast-water than in such containing 

 mineral salts, asparagin, tartrates, &c. 



We, therefore, made series of parallel cultures at various tempera- 

 tures, in air and in carbon dioxide, and all infected from the same tube, 

 using the following sugars and solutions : — Levulose, pure glucose, 

 cane-sugar, saccharon, lactose, maltose, dextrin, and a body known in 

 Grubler's catalogue as " dextrin-zucker-losung." The sugars were all 

 made up in 10 per cent, solutions, and definite quantities — equal in 

 each case — of the other ingredients added. 



Summing up the results of numerous experiments, it was found that 

 no growth occurred in any medium at temperatures of 35° C. and 

 upwards, except in the case of certain agar cultures, where rapid 

 growth occurred at and near 37° C. for a few days only. 



Cane-Sugar. 



The most striking results were obtained in all cases with cane-sugar,, 

 especially in a very pure re-crystallised form labelled " Saccharon," 

 though we also employed ordinary lump-sugar, and a coarse dark brown 

 moist sugar known locally as " Black sugar." 



Made up as Mayer's solution, the brown sugar rapidly became turbid 

 and viscous, and a dense gelatinous deposit of bacteria formed below 



* Attempts at infection were made in view of the alleged connection between 

 bacteria and certain diseases of beet and sugar-cane. See, for instance, ' Kew 

 Bulletin,' No. 85, January, 1894, p. 1, and ' Zeitschr. f . Pflanzenkrankh.,' 1897, 

 No. 7, p. 65. 



