Abstract
1. Nitric oxide is produced from nitrite and is utilized in place of the latter and it is presumable that nitric oxide is an intermediate in denitrification.
2. Dimethyl-p-phenylene diamine and p-phenylene diamine can act specifically as reducing agents where the quantity of nitrogen pro-duced corresponds to about twice as much as nitrite-N.
3. Gas production with the dime thyl-p-phenylene diamine-nitrite system is inhibited by KCN and p-chloromercuribenzoate. Effects of other various inhibitors were described.
4. The essential stages in the denitrifying process were discussed.
The expences for the work were aided partly by the Scientific Research Funds and by the Grant in Aid for the Scientific Research from the Ministry of Education.
