191 1] Carl L. Aisberg 105 



alone is offered as a source of carbon, the gallic acid formed as 

 a result of the tannic acid transformation is utilized in the metab- 

 olism of the organism — the greater the growth of the fungus, the 

 greater is the decrease in tannic acid. It is hkewise shown that the 

 duration of growth, the presence of other nutrients, and aeration — 

 factors influencing growth mass — were important considerations 

 with respect to the yield of galHc acid. 



An infusion of gall nuts contains, in addition to tannic acid and 

 galHc acids, other organic Compounds as well as inorganic salts. 

 When cultures are made in which the gall nut infusion is used as the 

 nutrient Solution, the tannic acid is transformed; but the gallic acid 

 is not at first utilized. The organism seems to elect the other 

 organic Compounds first and then some of the gallic is utilized. 

 There is, then, an election of food by the organism. 



If there is offered to Aspergillus niger or Penicillium sp. in a 

 nutrient salt Solution, 10 per cent. cane sugar along with 13 per cent. 

 tannic acid, then the sugar entirely protects the gallic acid formed, 

 from assimilation or use as food by the fungus. A 5 per cent. 

 concentration of sugar is not sufficient to protect the gallic acid, 

 during the growth interval employed. 



Experiments were also made in which the fermentation cultures 

 were kept under anaerobic, and also limited oxygen conditions, and 

 the results obtained were compared with those in which growth was 

 permitted under more favorable conditions of aeration and nutri- 

 tion. 



Regulatory Formation of the Enzyme Tannase 



LEWIS KNUDSON 



{Department of Botany, Cornell University, Ithaca, N. Y.) 



The work of Permi, Pfeffer, Katz, Went, Dox and others has 

 shown that the formation of enzymes is influenced markedly by the 

 nutrition of the organism. According to Dox, the production of 

 those enzymes that are not normally developed by the organism 

 cannot be induced in demonstrable quantities by any special nutri- 

 tion. This Statement is not in accord with the results obtained by 

 Went ; nor with the more recent work of Harden and Norris work- 



