340 A SLIME BACTERIUM FROM THE PEACH, ETC., 



tives of other sugars. The nature of the gum is ascertained 

 from the sugar which it produces upon hydrolysis. The sugar is 

 most readily determined by means of the osazones in cases of 

 bacterial gums and slimes, when other bacterial by-products are 

 present and when the quantity of material is usuall}^ small. The 

 solubility, the appearance, and the melting points of the osazones 

 are usually very characteristic. 



The slime was repeatedly dissolved in water and precipitated 

 with alcohol until a portion when hydrolysed at 70° C. with 

 dilute hydrochloric acid showed the absence of reducing sugars. 

 The hydrolysis of the gumm}^ constituent was effected by boiling 

 the slime with 5 % sulphuric acid for six hours. A slight humus- 

 like deposit was filtered off and the sulphuric acid was removed 

 by treatment with barium carbonate. From the clear filtrate 

 the barium salt of an inorganic acid was removed by alcohol. 

 The alcohol was distilled off and the solution after clarification 

 with aluminium hydrate was evaporated to small volume. The 

 preparation and separation of the osazones will be more readily 

 followed from the table on the next page. 



From the results set down in the table it is seen that the 

 sugars into which the essential carbohydrate of the slime hj'^dro- 

 lyses are arabinose and galactose. In these sugars the galactose 

 greatly predominated, the arabinosazone having been obtained in 

 relatively small quantity. 



In slimes which are obtained by growing bacteria upon the 

 surface of agar, there is always a danger of portions of the medium 

 getting into the slime. When large covered dishes are used, 

 drops of condensed water gather upon the cover and, unless 

 removed by sloping the cover as they form, may fall into the 

 solidifying medium, which is softened at that place and readily 

 comes away with the slime. The traces of agar, however, which 

 are thus accidentally gathered do not appear to influence the 

 determination of the constituents of the slime, j)robably because 

 the agar, which consists chiefly of pararabin, is not hydrolysed by 

 boiling with 5 % sulphuric acid — at least in the time (6-10 hours) 



