ALKALI-FORMING BACTERIA FOUND IN MILK. 
29 
pounds. The urea was sterilized through a Berkefeld filter, so there 
was no ammonium carbonate present as would have been the case 
if the ordinary method of steam sterilization had been employed. 
Ammonia was an end product from all three of these test substances, 
and with urea the only alkali end product possible. Keference to 
Table 10 shows that 13 of the cultures fermented hippuric acid, 8 
uric acid, and 41 urea. In addition to the 68 cultures of alkali- 
forming bacteria isolated from dairy products, the fermentation of 
the organic-acid salts was tried with 55 known cultures, namely, 37 
strains of dysentery, 6 of proteus, 6 of typhoid, 3 of paratyphoid, 
and 1 each of B. abortus, B. broncMsepticus, B. fxcalis alJcaligenes, 
and B. enteriditis. The results of the fermentation of the citric and 
lactic salts and litmus-milk reaction are given in Table 13. It is 
evident from the results that all the cultures fermented the citrate 
and a large number of them the lactate. Many of the cultures gave 
characteristic milk reaction of the alkali-forming group of bacteria. 
Table 13. — Fermentation of the sodium salt of citric and lactic acid together with the 
milk reactions of known cultures. 
Culture. 
Litmus-milk 
reaction, 7 days 
at 30° C. 
Ph value, 3 
days at 37° C. 
Culture. 
Litmus-milk 
reaction , 7 days 
at 30° C. 
Ph value, 3 
days at 37° C. 
Citric. 
Lactic. 
Citric. 
Lactic. 
6.8 
7.2 
Dysentery- 
Continued. 
8 
No change 
Slight acid 
No change 
.....do 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
8.6 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
Alkaline 
.....do 
do 
do 
do 
do 
Coagulated, acid. 
No change 
Alkaline 
Slight acid 
Coagulated, acid. 
do 
No change 
Alkaline 
do 
do 
do 
do 
No change 
do 
Slight acid: 
No change 
Slight acid 
do 
No change 
8.4 
8.8 
8.3 
8.3 
8.4 
8.3 
7.5 
7.4 
8.4 
7.3 
7.4 
7.5 
7.4 
8.5 
8.5 
8.5 
8.4 
7.3 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
7.4 
6.9 
8.6 
7.2 
7.0 
7.3 
7.0 
7.3 
7.3 
7.5 
7.3 
7.3 
7.0 
7.0 
7.3 
• 7.7 
7.3 
7.5 
7.3 
7.3 
7.1 
7.3 
• 7.3 
7.4 
7.4 
7.0 
7.3 
ACL 
9 
7.1 
ACN 
10 
7.4 
ACU 
11 
7.1 
ACV 
12 
do 
7.3 
ADE 
13 
Coagule ted, acid. 
Slight acid 
do 
Alkaline 
No change 
do../ 
do 
do 
Coagulated, acd . 
Slight alkaline . . 
Slight acid 
do 
do.. 
No change 
do 
do 
do 
do 
Slight acid 
No change.*. 
do 
do 
do 
Slight acid 
No change 
7.4 
ADG. ...... 
14 
7.3 
Typhoid: 
607 . 
15 
16... 
7.4 
7.5 
608 
17 
7.4 
Rowd 
M. T. S 
Hop 
Hop 22 
Paratyphoid: 
16 
18 
20 
21 
22 
7.1 
7.3 
7.2 
7.8 
23 
24 
7.0 
22 
25... 
26 
27 
7.0 
323 
7.0 
7.4 
B. abortus 
B. bronchisepti- 
cus. 
Dysentery: 
1 
28 
29 
30 
31 
32 
7.3 
7.3 
7.4 
7.3 
7.1 
2 
33 
7.5 
3 
34 
35 
36 
37 
7.3 
4 
7.3 
5 
7.3 
6 
7.0 
7 
38 
7.4 
The salts of organic acids not only serve as a source of carbon 
for the alkali-forming bacteria and, therefore, are valuable test 
substances, but their use need not be limited to the bacteria of 
this group. In fact, it seems probable that they may have an 
extensive application in the study of other groups of bacteria., 
