ALKALI-FORMING BACTERIA FOUND IN MILK. 31 
Table 14. — Reduction of nitrates and nitrites in simple and complex media — Contd. 
Culture No. 
112 
113 
111 
116 
117 
118 
119 
120 
121 
122 
123 
124 
125 
126 
128 
130 
131 
132 
133 
134 
135 
136 
137 
138 
139 
111 
112 
143 
144 
145 
146 
147 
303 
309 
314 
317 
319 
321 
322 
325 
326 
340 
353 
354 
356 
361 
362 
0.1 per 
cent 
pep- 
tone, 
J.02 per 
cent 
potas- 
sium 
nitrate. 
Nitrite 
test, 7 
days. 
0.2 per cent beef 
extract, 0.02 
per cent potas- 
sium nitrate. 
Nitrite 
test, 24 
hours. 
Nitrite 
test, 7 
days. 
0.1 per cent beef 
extract, 0.02 
per cent potas- 
sium nitrate. 
Nitrite 
test, 24 
hours. 
Nitrite 
test, 7 
days. 
Sudium nitrate, 
0.2 per cent; so- 
dium-lactate, 
0.25 per cent: 
sodium-dibasic 
phosphate, 0.1 
per cent. 
Nitrite 
test, 14 
days. 
Change 
in titra- 
tion. 
■ .yi> 
• .63 
• .92 
■ .79 
• .97 
•1.07 
■ .93 
• .85 
• .11 
■ .07 
• .97 
• .87 
-1 03 
-1.01 
■ .85 
•1.09 
■ .97 
- .93 
• .05 
■ -91 
■1.02 
■ .97 
- .89 
■1.15 
■1.10 
• .95 
■1.08 
- .70 
■1.07 
• .97 
-1.05 



•1.19 

- .88 
- .75 
- .94 
- .90 
-1.00 

.41 
• .84 
■1.10 
Sodium nitrite, 
0.2 per cent: so- 
dium lactate, 
0.25 per cent; 
sodium-dibasic 
phosphate, 0.1 
per cent. 
Ammo- 
nia test 
14 days. 
Change 
in titra- 
tion. 
- .57 
- .40 
■ .81 
- .99 
■ .77 
■1.20 
- .86 
■ .35 
■ .66 
-1.40 
■ .63 
- .99 
• -96 
- .84 
- .85 
■1.12 
- .68 
- .91 
- .62 
- .51 
- .87 
- .88 
- .63 
■1.01 
-1.33 
- .19 
-1.45 
- .72 
■1.01 
-1.34 
-1.00 
-1.51 


■1.52 
- .51 
- .26 
- .72 
■ .97 
.51 

.23 
.61 
.62 
.18 
.43 
It is interesting to compare the number of positive nitrite tests 
in the peptone nitrate broth, where only seven cultures gave a 
positive nitrite test after seven days, with the 0.2 per cent beef- 
extract nitrate broth where 47 out of a total of 68 cultures showed 
a nitrite test after seven days. This small number of reductions 
