GREIG SMITH. 



443 



tion was not very satisfactory, and so the viscosity of the cultures 

 was determined. The following table gives the time in seconds 

 during which 5 c.c. of the culture passed through a pipette with 

 a capillary orifice. 



The excessive viscosity of the media containing maltose and 

 glycerine was caused by transparent zoogloea masses or floating 

 films passing very slowly through the capillary point of the 

 pipette. The experiment shows that the bacterium can form 

 slime from levulose, dextrose, invert sugar, galactose, lactose, 

 maltose and glycerine; it had been already found that saccharose 

 must be included among these nutrients. 



Since glycerine served so well, and as it is comparatively easy 

 to eliminate from the slime, it was employed in the production 

 of a quantity of the gum. At the end of three weeks the mediumf 

 which had been kept at the laboratory temperature (14-17° C.) 

 contained floating slime-films, and a film adhering tenaciously to 

 the surface of the glass above the fluid. The films and the ropy 

 fluid were removed from the flask and evaporated down to about 

 200 c.c. In this the slime was precipitated by alcohol. The 

 coagulated slime was treated with water and the almost homo- 

 geneous slime was again coagulated with alcohol. Neither the 



*Peptone 0-25, sodium phosphate 0*2, potassium chloride 0-3, water lOOgrms. 



t Glycerine 50, peptone 5, sodium phosphate 2, potassium chlorid^^,; ■ 

 water 1000 grms. . ■^ • 



u LIBRARY 



