ALKALI-FORMING BACTERIA FOUND IN MILK. 
15 
Only the cultures which showed a slight P H change in medium A 
were run in medium C. From the results of the work it was evident 
that 44 of the 68 cultures of alkali-forming bacteria could ferment 
dextrose, but many of them to only a slight extent. The fermen- 
tation was slow with certain of the bacteria, as is seen in Table 6, 
which shows the P H value of 3 cultures in medium A. These cultures 
represent 3 types of fermentation. Culture 12 reached P H 4.5 after 
3 days' incubation at 30° C, while culture 319 reached P H 6.0 only 
after 10 days, and its highest hydrogen-ion concentration was P H 5.5. 
Culture 140 reached P H 6.5 in 10 days, which seemed to be its highest 
point, and did not show further change after 21 days' incubation. 
Table 6. — Three types of dextrose fermentations as shown by the hydrogen-ion concen- 
tration in terms o/Ph. 
Culture No. 
Days. 
1 
2 
3 
4 
5 
7 
10 
14 
21 
7.1 
7.0 
7.0 
7.0 
7.0 
7.0 
7.0 
7.0 
6.9 
12 
6.6 
6.9 
7.0 
5.6 
6.8 
7.0 
4.5 
6.8 
7.0 
4.5 
6.8 
6.9 
4.5 
6.6 
6.9 
4.5 
6.6 
6.8 
4.5 
6.0 
G.5 
4.5 
6 
(3.5 
4.5 
319 
5.5 
140 
6.5 
Table 7. 
■Comparison of the fermentation of dextrose in an extract broth and a synthetic 
medium. 
Dex- 
Dex- 
Dex- 
trose- 
trose- 
trose- 
sodium- 
sodium- 
sodium- 
Dextrose broth. 
ammo- 
Dextrose broth. 
ammo- 
Dextrose broth. 
ammo- 
Culture 
nmm 
Culture 
mum 
Culture 
nium 
No. 
phos- 
phate. 
No. 
phos- 
phate. 
No. 
phos- 
phate. 
7 days. 
21 days. 
14 days. 
7 days. 
21 days. 
14 days. 
7 days. 
21 days. 
14 days. 
10 
+ 
+ 
+ 
118 
_ 
_ 

145 

12. 
— 
+ 
+ 
119 
— 
— 
+ 
146 
— 
— 
+ 
31." 
— 
— 
+ 
120 
+ 
— 
+ 
147 
— 
— 

49 
+ 
— 
+ 
121 
+ 
+ 
+ 
303 
— 
— 

59 
+ 
- 

122 
— 
— 

309 
- 
- 

60 
_ 
_ 

123 
+ 
+ 
+ 
314 
_ 
_ 
+ 
61 
— 
_ 

124 
— 
— 
+ 
317 
— 
_ 

62 
— 
— 

125 
— 
— 
+ 
319 
+ 
— 
+ 
66 
— 
— 

126 
— 
— 
+ 
321 
— 
— 
+ 
72 
- 
- 
+ 
128 
+ 
- 

322 
- 
+ + 
73 
_ 
_ 

130 
_ 
_ 

325 
_ 
_ 
+ 
101 
— 
— 
+ 
131 
— 
— 
+ 
326 
— 
— 
+ 
102 
— 
— 
+ 
132 
— 
— 
+ 
340 
— 
— 

103 
— 
— 

133 
+ 
+ 
+ 
353 
— 
— 

104 
- 
- 
+ 
134 
+ 
+ 
+ 
354 
— 
- 

105 
_ 
_ 
+ 
135 
_ 
_ 
+ 
356 
_ 
_ 
+ 
106 
— 
— 

136 
— 
— 
+ 
361 
— 

+ 
107 
+ 
+ 
+ 
137 
+ 
+ 
+ 
362 
— 
— 
+ 
108 
— 
— 
+ 
138 
— 
— 
+ 
Ill 
- 
- 

139 
- 
- 

112 
+ 
_ 
+ 
140 
_ 
_ 
+ 
113 
+ 
+ 
+ 
141 
+ 
— 
+ 
114 

142 
— 

116 
— 
— 
+ 
143 
— 
— 
+ 
117 
— 
~~ 
+ 
144 
— 
~ 
+ 
Minus ( — )= alkaline. 
Plus ( + )=acid. 
Zero (0)=no change. 
