482 



SELMAN A. WAKSMAN 



case of A.fuscus and A. clavatus, both of which showed at the end 

 of thirteen days the lowest accumulation of amino nitrogen and 

 the highest accumulation of ammonia nitrogen, while B. mycoides 

 and Act. violaceus-ruber I and II gave the highest amounts of 

 amino- and the lowest of ammonia nitrogen. This theory does 

 not hold true for the Act. penicilloides which gave the highest 



TABLE 2 



Amino nitrogen and ammonia accumulation by microorganisms in a 2 per cent 



peptone solution 

 Milligrams of NHa-N and NHs-N per 100 cc. of solution 



PERIOD OP 

 INCUBATION 



days 

 At start 



6 

 13 



5 

 13 



5 

 13 



5 

 13 



5 

 13 



5 

 13 



5 

 13 

 38 

 38 



5 

 13 



OBGANISMS USED 



A . niger 



A . niger 



A. ochraceus 



A. ochraceus 



A . fuscus 



A . fuscus 



A. clavatus 



A. clavatus 



Citr. glaber 



Citr. glaber 



P. chrysogenum 



P. chrysogenum 



Act. penicilloides 



Act. penicilloides 



'^ct. violaceus-ruber I. 

 Act. violaceus-ruber II 



B. mycoides 



B. mycoides 



NHu-N 



40.26 



24,68 



29.90 



34.44 



42.20 



28.92 



17.90 



32.19 



23.19 



40.20 



48.12 



44.36 



71.10 



72.40 



149.50 



130.63 



129.25 



61.70 



119.20 



NHs-N 







7.00 

 77.56 



4.20 

 56.00 



5.68 

 108.36 



9.80 



103.60 



11.62 



48.68 



8.12 

 46.76 



6.18 

 42.36 

 25.20 

 22.60 

 21.00 

 22.40 



amino nitrogen and at the same time a fairly high ammonia 

 nitrogen accumulation. 



It is very possible that the organisms tested differ greatly in 

 their power to attack the peptone and in the production of 

 different nitrogen decomposition products; such organisms as 

 A. niger and A. fussus do not seem to be able to allow a large 

 accumulation of amino nitrogen, and either do not split off a great 

 deal of it or use it up, as soon as it is formed, with the production 



