Feb. 94,2923 
Stimulating the Growth of Azotobacter 
677 
Table VII .—Effect of CaC 0 8 upon nitrogen fixation 
Culture. 
Milligrams nitrogen per gram of dextrose. 
2 days. 
4 days. 
6 days. 
No CaCOa. 
CaCOa. 
No CaCOa- 
* CaCOa. 
No CaCOa. 
CaCOa. 
I BM. 
4.3 
5-3 
7.0 
8.9 
9. 1 
”•5 
3 BM. 
4-3 
4.9 
9.4 
14. 2 
14.9 
I 5 - 9 
222 M. 
4. 9 
6. 0 
6. 1 
8.0 
15- 9 
11. 0 
10 BP. 
i- 7 
•9 
5 - 2 
7 - 1 
9.1 
8. 1 
12 BE. 
4-3 
5-6 
5-6 
10. 0 
8.4 
232 H. 
6-3 
4. 6 
7 - 2 
7 - 2 
7.2 
7.2 
Average. 
4-3 
5 -o 
6- 75 
8-5 
11. 03 
, 0 - 35 
SUMMARY 
(1) A prompt and vigorous growth of Azotobacter can be induced in 
large quantities of liquid medium by sufficient aeration. 
(2) Aeration stimulates rapid nitrogen fixation by Azotobacter. 
(3) There exists a close correlation between the rate of dextrose fer¬ 
mentation and nitrogen fixation. 
(4) The presence of calcium carbonate is not essential in a medium 
used for aerating pure cultures of Azotobacter. 
LITERATURE CITED 
(1) Lipman, Jacob G. 
1904. EXPERIMENTS ON THE TRANSFORMATION AND FIXATION OF NITROGEN BY 
bacteria. In N. J. Agr. Exp. Sta. 24th Ann. Rpt. [19021/03, p. 
217-285, 2 pi. 
1909. azotobacter studies. In N. J. Agr. Exp. Sta. 29th Ann. Rpt. [19073/08, 
p. 136-143. 
(3) Hoffman, Conrad, and Hammer, B. W. 
1909. Two new methods for growing azotobacter. In Centbl. Bakt. [etc.], 
Abt. 2, Bd. 24, No. 5/7, p. 181-183. 
(4) SOhngEn, N. L. 
1914. UMWANDLUNGEN VON MANGANyERBINDUNGEN UNTER DEM E 1 NFLUSS 
mikrobiologischer prozesse. In Centbl. Bakt. [etc.], Abt. 2, Bd. 
40, No. 22/25, p. 545 - 554 , 3 pi- 
(5) Shaffer, Philip A. 
1914. on the determination of sugar in blood. In Jour. Biol. Chem., v. 
19, no. 2, p. 285-295. 
(6) Bonazzi, Augusto. 
1919. ON NITRIFICATION. II. INTENSIVE NITRIFICATION IN SOLUTION. In JotlT. 
Bact. v. 4, no. 1, p. 43-59, 2 fig- References, p. 58-59. 
(7) Allen, E. R. 
1919. SOME CONDITIONS AFFECTING THE GROWTH AND ACTIVITIES OF AZOTO¬ 
BACTER chroococcum. In Ann. Mo. Bot. Gard. v. 6, no. 1, p. 1-44, 
2 fig., 1 pi. Bibliography, p. 42-43. 
1920. ON CARBOHYDRATE CONSUMPTION BY AZOTOBACTER CHROOCOCCUM. In 
Ann. Mo. Bot. Gard,, v. 7, no. 1, p. 75-79, 1 fig. Literature, p. 79. 
26551—23-8 
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