90 ROYAL SOCIETY OF CANADA 



Varieties of Groups I and IV had strong œrobic tendencies. In 

 liquid media they grew in the surface layers and rendered these viscous, 

 and the viscosity gradually increased with age. On several occasions 

 when making subcultures, some of the transferred culture was deposited 

 ^ in the deeper layers of the culture medium, and after sufficient incubation 

 no growth appeared, which seemed to show that the organisms had to 

 be placed near the surface to develop. 



The varieties belonging to Groups II and III grew as well with 

 as without oxygen. They grew throughout the liquid media and ren- 

 dered all of it equally viscous. On solid media they developed very 

 viscous growth under anaerobic conditions. Oxygen is not, therefore, 

 a factor in all viscous fermentations. 



When the production of slime took place in slightly alkaline media 

 the viscosity was marked and permanent, whilst that in acid media was 

 slight and had a tendency to disappear if the acid increased to any 

 extent. 



Sugar did not seem to be a necessary ingredient of the media for 

 the production of the slime condition, for cultures became viscous in 

 sugar-free peptone solutions. It was true that the viscosity in peptone 

 solutions was slight, but growth was also rather meagre. Better results 

 were obtained in bouillon in which the muscle sugar had been previously 

 fermented and which was tested for sugar with a very active gas- 

 producing colon bacillus with negative results. In this sugar-free medium 

 the slime-producing organisms grew very well and rendered the whole 

 medium very viscous. 



Varieties of the first group were not greatly influenced by the 

 presence of various sugars in peptone solutions. Varieties 7, 8, 9, 

 and 10 grew better when sugar was present and portions of the sugar 

 were fermented, growth was more luxuriant and viscosity was as great 

 as that in milk or broth, but as soon as the acid produced by the fer- 

 mented sugar reached a certain degree, the viscosity disappeared. 



The following experiments were performed in order to ascertain 

 if the slimy change in milk was due to soluble enzymes. Tight-fitting, 

 collodion sacks were suspended in Erlenineyer flasks two-thirds filled 

 with milk. The sack was filled with milk to the same height as the 

 milk in the flask; the neck of the flask, and the neck of the test tube,, 

 to the bottom of which was attached the collodion sack, were plugged 

 with cotton and sterilized. The milk in the flask was inoculated with 

 the slimy organisms and kept at a temperature of 25° C. The milk 

 in the flasks behaved like the cultures in milk, but the milk in the- 

 collodion sack never became viscous, although the experiments were car- 

 ried on for 6 to 8 months. In all acid-producing varieties the milk 



