FIXATION OF NITROGEN BY FUNGI 



189 



Adamson. T\Tiere solutions were measured with a pipette, 

 a special pipette was provided for each separate case or purpose 

 and was never used for any other. The test tubes in which 

 the cultures were grown and digested (both being the same) were 

 first scrubbed then boiled with cleaning fluid, then allowed to 

 stand 24 hours or more and again scrubbed out and rinsed with 

 tap water and finally with distilled water. Jena tubes should 

 have been provided for this purpose but unfortunately were not 

 available and much loss and trouble resulted through breakage. 



TABLE 7 



Experiment F. Aspergillus cultures in Czapek's solution containing 3% dextrose. 

 Each culture contained 5 cc. of the solution, to lohich was added 1 cc. or 2 cc. of the 

 1 mgm. ammonia solution 



In the analysis of the above only 2 to 3 drops of H2SO4 were added to hold the 

 ammonia while the mixture was evaporated until SO2 fumes appeared; then 

 the remainder of the chemicals was added and the digestion completed. This 

 made the digestion much easier and reduced the time considerably but it may 

 also have caused the loss of nitrogen. 



Since the amount of material to be digested in these analyses 

 was greater than that in the experiments described by Folin it 

 seemed necessary to increase the amounts of chemicals and the 

 length of time was necessarily increased, often requiring over 

 an hour for completion. But with practice I found it possible 

 to reduce the time to half an hour for digestion. It seemed 

 best to increase the time for blowing over to fully twenty minutes 

 or double the time taken in Folin's work. WTiile I doubled the 



