Lewis Knudson 



179 



methods, and the cultures incubated at 28° C. 

 tained are included in table IX. 



The results ob- 



TABLE IX. 



ORGANISM 



DURATION 



days 



GALLIC ACID 



IN CULTURE 

 SOLUTION 



GALLIC ACID 

 USED 



DRY WEIGHT 

 OF FUNGUS 



Series I. Solution B -\- 10 per cent sugar + gallic acid. 



Check 



Aspergillus niger. 

 Penicillium sp. . . . 

 Aspergillus niger. 

 Penicillium sp.. . . 



2.837 

 2.837 

 2.837 

 2.837 

 2.837 



none 

 none 

 none 

 none 



0.3491 

 0.1109 

 0.4589 

 0.3676 



Series II. Solution B -\- gallic acid. 



Check 



Aspergillus niger -. 

 Penicillium sp. . . . 

 Aspergillus niger. 

 Penicillium sp. . . . 



0.337 



not detected 



1.363 



0.280 



0,1000 

 0.010 

 0.3434 

 0.108 



A glance at the table reveals the fact that both Penicillium sp. 

 a,nd Aspergillus niger elect cane sugar and leave behind in the culture 

 solution the gallic acid. Cane sugar is therefore proven conclu- 

 sively to protect the gallic acid. It is of interest to note that the 

 addition of the sugar permits of a more rapid and more extensive 

 growth during the ten-day period. 



VIII. INFLUENCE OF AERATION. 



Limiting supply of oxygen. VanTieghem^' stated that under 

 aerobic conditions the tannic acid was utilized directly, and that 

 the small amount of gallic acid formed was also assimilated. The 

 preceding experiments and others of the writer, not here men- 

 tioned, show that transformation of the tannic acid occurs even 

 when all the growth is on the surface. However, if sugar is not 

 offered with the tannic acid, the increased growth may, as shown, 

 be at the expense of the galUc acid formed. If the tannic acid is 



'" hoc. cit. 



