344 A SLIME BACTEKIUM FROM THE PEACH, ETC., 



ised witli sodium liydrate, when a precipitate settled out. This 

 was treated with water and filtered. The solution, which was 

 neutral to litmus, was coagulated by alcohol and precipitated by 

 barium hydrate (not by barium chloride), neutral lead acetate 

 and basic lead acetate. These precipitates were cnrdy, like other 

 gum precipitates, and when considered in conjunction with the 

 method of separation (/.<^, the solubility of the carbohj'drate in 

 acid alcohol) show that the constituent had been produced by 

 the bacterium. 



Hitherto the slime had been formed on media or in solutions 

 containing saccharose without which no pronounced formation of 

 slime occurred. Other sugars and carbohj^drates had not, how- 

 ever, been tested, and therefore experiments were made to 

 determine what other substances could replace saccharose. To 

 •dilute potato-extract agar, simple peptone agar and ordinary 

 nutrient agar, small quantities of the following substances were 

 added: saccharose, levulose, dextrose, galactose, maltose, lactose, 

 ratfinose, mannite, starch, inulin, dextrin and glycerine. The 

 potato-extract medium did not give results so sharply as the 

 ordinary nutrient agar, probably because that medium contains 

 reducing sugars and other substances that assist gum-formation. 

 They, however, served to corroborate the results obtained with 

 ordinary meat-extract-peptone agar and simple peptone agar. 

 Slime was produced from all the substances except lactose, 

 starch and inulin. 



Carbon dioxide was imperceptibly evolved during the slow 

 fermentation of saccharose. Its presence in the air of the culture 

 flask w^as shown by drawing the air above a 5 days' culture 

 through baryta water contained in an attached flask. The usual 

 precautions were taken to exclude aerial carbon dioxide when the 

 medium was infected, and it is needless to say that carbonates 

 were absent from the medium. 



The acids that are produced from saccharose simultaneously 

 with the gum were found to consist chiefly of lactic and butyric, 

 with traces of succinic, acetic and formic. The ratio of volatile 



