18 
BULLETIN 303, IT. S. DEPARTMENT OF AGRICULTURE. 
In order to test the value of this medium as compared with the bile 
tube method, 43 samples of ice cream were examined. The results 
are shown in Table 11. It may be seen that the colon count as deter- 
mined on litmus-lactose-asparagin agar was higher than the number 
estimated from bile tubes in 41 of 43 samples. In most samples the 
number determined from the asparagin plates was much higher; in 
one sample it was 47 times as high as the number calculated from 
bile tubes. 
Table 11. — Comparison of the number of Bacillus coli in ice cream determined by the 
bile-tube method and on litmus-lactose-asparagin-agar plates. 
Bile 
medium. 
Litmus-lactose-asparagin-agar plates. 
Cultures 
c 
t 
B. coli. 
B.coli. 
Cul- 
tures 
picked. 
picked 
which 
form gas 
in lactose 
Per cent 
gas 
formers. 
broth. 
0Q 
1 
15,400 
86,000 
200 
154 
80 
146 
78 
94.80 
97.50 
9 
3 
50 
4 

100 
1 
1 
100.00 
5 
500 
8,000 
8 
8 
100.00 
6 
500 
900 
9 
9 
100.00 
7 
1,000 
2,500 
22 
22 
100.00 
8 
5,000 
13,000 
12 
12 
100.00 1 
9 
750 
2,900 
29 
29 
100.00 
10 
2,500 
5,600 
53 
51 
98.01 
11 
1,000 
• 7,200 
62 
57 
91.93 
12 
250 
400 
4 
4 
100.00 
13 
1,000 
12,000 
12 
11 
91.61 
14 
2,500 
11,900 
86 
80 
93.02 
15 
7,500 
123,000 
91 
85 
93.29 
16 
to 
3,000 
3 
3 
100.00 
17 
50 
3,900 
39 
34 
87.17 
18 
750 
39,000 
38 
38 
100.00 
19 
250 
5,000 
5 
5 
100.00 
•'() 
750 
1,000 
2,400 
7,700 
?1 
99 
250 
2,400 

I 
Bile 
medium. 
B. coli. 
5,000 
50,000 
5,000 
100,000 
100,000 
1,000 
250 
1,000 
100 
2,500 
500 
500 
250 
75 
1,000 
250 
75 
50 
75 
100 
750 
Litmus-lactose-asparagin-agar plates. 
B. coli. 
108,000 
120, 000 
75,000 
300,000 
600, 000 
47, 000 
5,600 
6,500 
1,200 
15,000 
3,000 
3,000 
1,730 
550 
2,530 
2,350 
20 
(2)0 
100 
230 
820 
Cul- 
tures 
picked. 
Cultures 
picked 
which 
form gas 
in lactose 
broth. 
Per cent 
gas 
formers. 
i In T fo dilution. 
2 In T V dilution. 
