446 A VARIABLE GALACTAN BACTERIUM, 



colony were transferred to two molten glucose-gelatine tubes. 

 One of these was incubated for 3 days at 30°, the other for a 

 similar time at 22°. The tubes were then used for making 

 dilutions in glucose-gelatine, which were poured into Petri-dishes. 

 The colonies that developed from the culture that had been incu- 

 bated at 22° were entirely of the normal or gelatinous type, while 

 those from the culture that had been incubated at 30° were all of 

 the slimy type. From this it is evident that the bacteria were 

 the same, and that the incubation in glucose-gelatine at 30° had 

 so influenced the organism that it produced a soluble, yellowish 

 slime instead of an insoluble, transparent, gelatinous carbohydrate. 

 The insolubility of the carbohydrate, by restraining the growth 

 of the cells, also prohibits the production of colour, as I have 

 observed in many cases. 



The identit}^ of the types was furthermore proved by the 

 examination of the gum produced from each. That from the 

 slimy bacterium was also a galactan, and it gave the same 

 chemical reactions as the other. In both cases the gum had been 

 obtained by digesting the slimes in the autoclave, so that they 

 were both in the soluble condition. 



As neither the original nor the modified type appears to have 

 been described, I propose the name Bacilhis Atherstonei from its 

 having been found in Stj^ychyios Atherstonei. 



Cultural Characters. 



Sha2)e, etc. — The bacteria appear as plump rods, with rounded 

 ends, and when taken from saccharose-peptone-fluid and stained, 

 measure 0-7-0-8 : l-^^x; in this medium threads up to 7-5/i long 

 have been observed. In the absence of sugar the cells are thin 

 and sometimes vacuolated. In saccharose-fluid media the bacteria 

 are motile and move with a waltzing and wriggling motion. The 

 flagella could not be stained. Spores are apparently not formed, 

 and the cells are not coloured by the Gram method of staining. 



Temperature, etc. — The bacteria grow at 30° C. and at lower 

 temperatures, but at 30° gum or slime is not formed in fluid cul- 

 tures. It is produced at and below 22\ The organism grew to 



