56 
THOMPSON YATES LABORATORIES REPORT 
These results are a fair reason for concluding that by means of a lactose bile 
salt agar, and an incubation temperature of 42 0 C, one can inhibit almost all the 
intestinal organisms except B. c. c, and that B. c. c. will grow as well on this medium 
as on carbol agar. 
But the correctness of this conclusion is rendered doubtful by the following 
experiments : — 
A pure culture of the Escherich strain of B. c. c. (given me by Dr. Herbert 
Durham) was plated in nutrient agar, carbol agar, and lactose bile salt agar. 
In the first experiment the solution was not dilute enough, and the nutrient 
agar and carbol agar plates were overcrowded, there being more than 1,600 colonies 
on a plate. But even with this large number present in the solution not more than 
20 had grown on a lactose agar plate. 
In a second experiment the numbers were : — 
Nutrient agar Carbol agar i °/ oo Bile salt lactose agar 
324 
338 
332 
5 plates 
No growth 
33' 
In a third similar experiment the numbers were : — 
Carbol agar I °j m Bile salt lactose agar 
9 3 plates 
Nutrient aga 
l6l 
172 
No growth 
[40 
Similar experiments made with a pure culture of B. t. a. gave results 
Nutrient agar 
Overcrowded, more 
than 3,000 per plate. 
Carbol agar I %, 
2 per plate. 
Bile salt lactose agar 
Overcrowded, more 
than 3,000 per plate. 
Nutrient agar 
139 
166 
133 
I46 
II 
Carbol agar I °/ 0 , 
O 
O 
O 
Bile salt lactose agar 
129 
H3 
142 
138 
