1923] 



KLOTZ — NITROGEN METABOLISM IN FUNGI 



355 



different nature of the change in hydrion concentration, the 

 slower consumption of sugar by the Sphaeropsis, and the different 

 rates of assimilation of the ammonium and nitrate ions. The 

 Diplodia gradually increases the [h] from P H 4.0 to P H 2.7 during 

 the 38 days of incubation, while the Sphaeropsis during the first 

 6 days slightly increases the [h] from P H 4.0 to 3.8 and then 

 during the succeeding 8 or 9 days decreases it from P H 3.8 to 

 Ph 5.8. The disappearance of glucose from the medium of the 

 Diplodia cultures takes place about the ninth day, but not until 



2 S 4- S to 



6 9 10 II U 



/DAYS 



Fig. 15. Ammonium N in 50 ml. media. Diplodia natalensis. 



the fifteenth day in the cultures of Sphaeropsis; and the ap- 

 pearance of autolytic predominance, as indicated by loss of 

 weight, occupies the same relative position. Diplodia assimilates 

 the NH« faster than it does the NO, of the NH«NO, molecule, 

 while the opposite is true for Sphaeropsis. This largely accounts 

 for the different curves for active acidity. The different rate of 

 consumption of dextrose and autolytic effects may also play 

 some part in this change of [h]. 



The curves for hydrion concentration of the culture solution 

 of the second and third Aspergillus series on the KNOi medium 

 are peculiar in that they show an increase of 0.6 P H the first day, 

 followed by a fall of 0.3 to 0.5 P H during the next 4 days and then 

 a gradual rise in P H value to the end of the experiment. The 



