BY K. GKEIG SMITH. 835 



precision. To complete my work upon Bad. sacchari, I deter- 

 mined to reinvestigate the slime. 



Experiments with other slimes had led to the preparation of a 

 medium containing potato juice 100 c.c, glycerine 50grm., tannin 

 3 grm., agar 20 grm., and tap- water to make a litre. A pre- 

 liminary sowing of BacL sacchari upon a plate of this medium 

 showed that it produced a luxuriant slime which did not adhere 

 to the medium. In view of this favourable result, large plates of 

 the medium were sown with the bacteria. The most convenient size 

 of Petri dish measures 15x2 cm., and easily holds 100 c.c of 

 agar medium. When larger dishes are used there is always too 

 much condensation of moisture upon the cover. The drops of 

 water that gather fall into the solidifying medium which is 

 softened locally and the soft agar is removed with the slime. 

 The infected plates were maintained at the laboratory temperature 

 (18°-20°). Upon the fifth day 135 c.c. of a thick slime were 

 removed, two days afterwards another 58 c.c. were gathered, and 

 on the tenth day another 20 c.c, making a total of 213 c.c. of 

 slime which had been obtained from a litre of medium. 



The slime was freed from glycerine and other matters by pre- 

 cipitation with alcohol, resuspension in water followed by a 

 second treatment with alcohol. As the slime was acid and 

 coagulation with the alcohol was not complete, it was nearly 

 neutralised with potassium hydrate. Neutralisation to phenol- 

 phthalein or to litmus caused a darkening of the slime from the 

 tannin contained in it, so care was taken to maintain the slime 

 just sufficiently acid to prevent any prominent change of colour. 

 The slime was rather deficient in saline matter, as was evidenced 

 by the alcohol producing a "milk," but the addition of potassium 

 chloride and the warming of the alcoholic fluid induced a com- 

 plete coagulation. 



After the second coagulation, the slime was tested for reducing 

 sugars, and as none were found the coagulated slime was treated 

 with water until a homogeneous emulsion was obtained. This 

 was heated on the water-bath to expel the bulk of the small 

 quantity of alcohol that had adhered to the coagulum. The 



