ON NITRIFICATION 499 



of nitrogen oxidation which follows the absorption and leads to 

 the formation of nitrous acid and its salts. 



REFERENCES 



AsHBY 1907-1908 Jour. Agric. Sci. (Cambridge) 2, 52-67. 

 BiEjERiNCK AND Van Delden 1903 Centr. f. Bakter., 2 Abt., 10, 33-67. 

 BoNAZZi 1919a Botan. Gazette, 68, 194-207. 

 BoNAzzi 1919b Jour. Bact., 4, 43-59. 



BoxjLLANGER AND Massol 1903 Annales d. I'lnstitut Pasteur, 17, 492-515. 

 BouLLANGER AND Massql 1904 Annales d. I'lnstitut Pasteur, 18, 181-196. 

 DucLAUX 1896 Annales de I'lnstitut Pasteur, 10, 414r-416. 

 GiBBs 1919 Soil Science, 8, 427-471. 



GoDLEWSKY 1892 Bull. Intern. Acad. Scie. Cracovie, 408-417. 

 GoDLEWSKY 1895 Bull. Intern. Acad. Scie. Cracovie, 178-192. 

 Hopkins and Whiting 1916 Bull. 190, Illinois Agric. Exper. Stat., 39&-406. 

 LoEW 1891 Botan. Central., 46, 222-223. 

 Macleod and Haskins 1906 Jour. Biol. Chem., 1, 319-334. 

 Winogradsky 1890 Annales de I'lnstitut Pasteur, 4, 257-275. 

 WiNOGRADSKY AND Omeliansky 1899 Centr. f. Bakter., 2 Abt., 5, 329, 

 377, and 429. 



