620 THE GUM FERMENTATION OF SUGAR CANE JUICE, 



potato, coccoid involution forms were noted on the second day. 

 On this medium the growth is at first moist glistening, but after 

 some weeks it became a whitish folded skin adhering firmly to 

 the medium. The optimum temperature lay between 25° and 30°. 

 The presence of saccharose is absolutely necessary for the forma- 

 tion of gum; no other sugars induce the mucoid fermentation. 

 Saline substances are favourable to the fermentation, but these 

 are not absolutely essential, since in their absence sugar solutions 

 can form gum. Albuminoids are likewise not absolutely neces- 

 sary in the fermentation. The by-products are mannite, lactic 

 acid, butyric acid and carbonic acid. Only a small part of the 

 saccharose is converted to dextrose. 



The Affinities of the Bacillus. 



Fritz Glaser has not described his bacterium at all fully, and 

 he did not investigate his gum with any detail, but from the fact 

 that it forms (amyll) alcohol and no lactic acid it is evidently 

 different from that which I have investigated. 



Both Ritsert's and Happ's organisms are like one another. 

 They were separated from the same kind of infusion, they show 

 a similar variability of form according to the medium; they pro- 

 duce acids and they invert saccharose. With regard to the 

 inversion, Ritsert has not described the product of inversion 

 otherwise than as a dextro-rotatory body capable of reducing 

 Fehling's solution, while Happ said that only a small part of the 

 saccharose was inverted. The byproducts in the fermentation of 

 Happ's bacillus are mannite, lactic acid, butyric acid and carbonic 

 acid. Ritsert did not identify his acid, and does not mention 

 mannite. I can find no mention of the nature of Happ's gum 

 beyond its being soluble in water, insoluble in alcohol and ether, 

 and having the composition (C^Hj o05)u. Ritsert's was optically 

 inactive. 



Although one cannot identify these two organisms by their 

 enzymic activities, it is possible from their cultural characters 

 that they are varieties of one common type, and that is possibly 

 Bac. vulgatus, to which my organism is probably also related. 



