PRESUMPTIVE TEST FOR BACILLUS Co LI 



295 



Dry the precipitated salts first on the water bath and then in an oven kept at 100 

 C. Powder in a mortar and keep in a tightly stoppered, wide mouth glass bottle. 

 Purify if necessary, by redissolving in a small quantity of warm alcohol and again pre- 

 cipitating with a large excess of ether. 



The author's experiments with bile agar suggested the use of bile 

 itself with i per cent of lactose as a liquid to replace Smith solution, 

 thus making a much more effective medium which would be cheaper 

 and easier to prepare than the latter solution. In the following experi- 

 ments the results with the new bile lactose medium is compared with 

 plain Smith solution, Smith solution containing sodium taurocholate, 

 and the same solution containing sodium glycocholate. 



It is evident that the presence of either or both of the bile salts 

 favors the growth of B. coll in Smith solution by inhibiting the growth 

 of other bacteria. A proper medium, may, therefore, be made by 

 adding to Smith solution 9 per cent of Platner's crystallized bile 



TABLE 3 . 



