BACILLUS COLI AND SALTS OF BILE 
47 
had settled to the bottom. The supernatant liquid was plated, i c.c. being put into 
each plate. The plates were incubated at 42 0 C, and examined after 48 hours. 
The plate was covered with colonies of various kinds. 
There was no growth in this plate. 
II. Pure cultures of B. c. c. {A, B, C, and D) were diluted with sterile water, 
and 1 c.c. of the dilution was put into each plate. 
A. Nutrient Agar- 
ic colonies \ 
i°4 » 
Nutrient Agar 
Bile Salt Agar 
months old. 
Bile Salt Agai 
2 
3 
B. Nutrient Agar 
1 month old. 1 
2 
3 
Bile Salt Avar 
C. Nutrient Agar 
12 days old. 1 
2 
3 
Bile Salt Agar 
1 
2 
3 
D. Nutrient Agar 
24 hours old. 1 
2 
3 
Bile Salt Agar 
65 colonies 
151 
94 „ 
356 colonies 
912 „ 
420 „ 
500 „ 
35 colonies 
29 » 
19 „ 
16 colonies 
28 „ 
25 „ 
1 16 colonies 
I3 6 » 
102 „ 
57 colonies 
121 „ 
53 » 
Average 138 
Average 103 
Average 56.2 
Average 536 
Average 27 
Average 23 
Average 1 1 8 
Average 77 
When endeavouring to estimate the value of this medium, in the case of 
mixtures containing B. c. c, a difficulty arose from the fact that nutrient agar cannot 
be used as a standard. So for sewage, river water, &c, carbolic agar, 1 °/ 00> was taken 
as the standard, because it is said that carbolic acid in this percentage practically gives 
the same results as nutrient agar in the case of pure cultures of B. c. c. 
