BY THOS. STEEL. 629 



From a consideration of the foregoing it will be seen that gum 

 levan differs from iniilin in its properties about as much as the 

 latter does from starch. The most striking points of resemblance 

 between levan and inulin are the [aj^ and the production, on 

 hydrolysis, of levulose only. 



The figures following show the effect of the growth of the 

 bacillus in a solution of sucrose of 10 per cent, strength. 



After removal of the gum by precipitation with alcohol, and 

 concentration of the saccharine solution, the residual syrup 

 obtained was found to contain for each 100 parts of sucrose 

 originally present : — 



Sucrose ... ... ... ... ... 5*4 



Dextrose ... ... ... ... 414 



Levulose .. ... ... ... ... 20*6 



It is thus seen that during its growth the bacillus has inverted 

 the sucrose, and then assimilated levulose. As sucrose, on 

 inversion, yields equal proportions of dextrose and levulose, the 

 difference between these two sugars in the residual syrup repre- 

 sents the levulose which has been used by the bacillus, and 

 amounts to 20*8 per 100 original sucrose. If there were as much 

 levulose present as dextrose, the sum of the two would be 82*8, 

 which is equivalent to 78 "7 of sucrose. This proportion, with the 

 5*4 still present, leaves 15*9 of sucrose not accounted for. A 

 little of this will be due to mechanical losses during manipulation, 

 and the remainder, which may be stated as at least 10 per cent., 

 represents sucrose used up by the bacillus in addition to th© 

 missing 20*8 of levulose. These results were checked by the 

 examination of several different cultures, and in each case results 

 of a similar nature were obtained. 



In a culture made in 20 per cent, solution of sucrose, the 

 growth of the bacillus was not nearly so abundant as in those 

 made in 10 per cent, solutions, and the transformation of sucrose 

 correspondingly less complete. 



In the disease known as " gumming " in sugar cane, on cutting 

 the stalks across the fibro-vascular bundles are found to be 



