300 NINETEENTH REPORT. 



METABOLISM. 



Changes in Nitrogenous Media: 



When cultured upon a medium containing either organic or inorganic 

 nitrogen, one of the end products of metabolism is ammonia. Tlie re- 

 action of the medium which is at first acid is slowly changed to alkaline. 

 Thus, in a series of clover-juice cultures (100 cc. in a liter flask) the 

 reaction changed, viz.. 



'Fuller's scale. Titrations made cold, using phenolphthalein as an indicator. 



In another series of clover-juice cultures the reaction proceeded as 

 far as 9° alkaline. A quantitative analysis of the ammonia content gave 

 .0130%. If the 9° alkalinity is calculated as being entirely due to 

 ammonia, it would be equivalent to .0153%, the difference between this 

 and the quantitative determination being within the limit of experimental 

 error. 



Cultures growing on litmus-lactose agar caused the litmus to begin to 

 turn blue within four days. After two weeks the blue coloration of the 

 litmus had jiermeated the agar for considerable distance beyond the 

 region of fiuigus growth, indicating the presence of an extra-cellular 

 protein-splitting enzyme resulting in the formation of ammonia which 

 causes the litmus to turn blue; also that this enzyme can diffuse to a 

 considerable degree through the agar. 



After about a month the fungus usually stops growing in the clover 

 juice. In order to determine the cause of this the following experiments 

 were performed: 



Clover juice liquid upon which the fungus had been growing for five 

 weeks was made sterile by passing first tlirough paper and then through 

 a sterile Berkfeld filter. The reaction of this liquid was 5° alkaline. 

 To a 20 cc. portion of this was added 5 cc. of a sterile 10% glucose solu- 

 tion, thus making a medium with a concentration of 2% sugar. This 

 was then heavily inoculated with spores from a 12 day old culture. A 

 similar inoculation was made into the liquid to which no glucose had been 



