486 



SELMAN A. WAKSMAN 



carbohydrates obeys the law of autocatalysis, while, in the ab- 

 sence of sugar, the variations are much greater, as shown in 

 figure 2. The normal growth of the organism is disturbed in the 

 absence of available carbohydrates when the organism has to 

 attack the protein molecule niot only for the nitrogen require- 

 ment, but also for its carbon supply. The quantities of ammonia 

 obtained from the first to the fifth day, in the absence of sugar, 

 are less than the calculated values, perhaps due to the fact that 



C / £ 3 ■>■ S 6 7 S S /O // /e /S /* /S /a/7 O / a S f^ 5 C 7 S 9 /a // /^ /3/-f/S/6/7/S /s> 



//7Ci/da;^/a/? //7 /)ays 



//76c/^a'//(p/7 //7/7ay5 



Fig. 1, Ammonia Accumulation by A. Fig. 2. Ammonia Accumulation by A. 

 niger in the Presence of Sugar niger in the Absence of Sugar 



it may take some time before the organism can begin to function 

 normally when it has to derive its energy from the protein mole- 

 cule; from the ninth till the sixteenth day, after the ammonia 

 accumulation reached 70 mgm., there is another deviation of the 

 calculated from the observed data. A similar but slighter devia- 

 tion is observed also in figure 1, after the amount of ammonia 

 reached 70 to 75 mgm. This may be either due to the exhaustion 

 of the energy supply in the medium, or to the formation of a new 

 autocatalytic curve. Further work on this subject continued for 

 a much longer period of time would therefore be desirable. 



