BY R. GREIG SMITH. 611 



is a ratio of 4*06 : 0-071 :: 57 : 1, and if some allowance is made 

 for the lactic acid included in the volatile acids, it is evident 

 that the bacillus forms about 60 times more lactic acid than 

 volatile acids. 



Mannite is not a Byproduct in the Gum Fermentation. 



In the mucinous fermentation of beet juice by some bacteria, 

 as, for example, Leuconostoc mesenterioides, the sugar is fermented 

 partly to dextran, or fermentation-gum, of which there are two 

 kinds, one a soluble form, the other an insoluble modification, and 

 partly to mannite. In order to see if mannite was a by-product 

 in the fermentation of sugar by this bacillus, several culture 

 solutions were freed from gum, and after evaporation to a syrupy 

 consistency, were extracted with strong hot alcohol. No mannite 

 crystals could be obtained from any of the cultures. The syrupy 

 residue of one, however, after standing for a week, contained a 

 number of feathery tufts of needle-shaped crystals which might 

 have been mannite. The whole syrup was dissolved in water 

 and the sugars fermented out with a pure culture of Saccharo- 

 onyces cerevisice I. The yeasts were then filtered off with the aid of 

 aluminium hydrate. Mr. Steel kindly tested the rotation of the 

 solution before and after the addition of borax. A very slight 

 Isevorotation was observed; the mannite, if present, was apparently 

 in so small an amount that it could not be definitely determined. 

 He subsequently tested a solution obtained from a culture con- 

 taining 46 grms. of saccharose, and could find no evidence of 

 mannite. It is, therefore, apparent that the bacillus does not 

 form mannite from sugar. The crystals observed in the syrup 

 were probably dextrose. Mannite was carefully tested for, 

 because a gum-producing organism, ^Bac. gummosus, Happ, forms 

 this hexatomic alcohol in sugar solutions. 



Ordinary alcohol is likewise not a product of the fermentation. 

 A litre culture was distilled with chalk, and in the first 50 c.c. 

 of distillate, which had a sp.g. of 1*0008, no iodoform reaction 

 could be obtained. 



