434 BACTERIOLOGY. 
jected to the usual tests for the recognition of the 
bacillus typhosus, and have always corresponded in 
all their reactions to those given y the typical typhoid 
bacillus. 
Esnrer’s Meruop.' As laner himself gives no 
very definite details as to the steps to be taken in 
making up his medium, those working with it have 
developed their own modifications. We found the 
following method to give satisfactory results : 
1. Grate 0.5 kilogramme of small potatoes to a fine 
pulp, add 1 litre of water, and allow the mixture to 
stand in a cool place over night. 
2. Mash thoroughly (meat-press is best) and strain 
through a fine cloth. This must be done when the 
mixture is cold or the swelling of the starch-granules 
will prevent the filtering process. 
3. Boil the filtrate and filter again. 
4, Add 10 per cent. of gelatine and dissolve by 
boiling. 
5. Test for the acidity. Elsner used litmus as an 
indicator, and advised that the medium be of such an 
acidity as to require the addition of 2.5 c.c. of deci- 
normal hydroxide solution to make it neutral. If 
more than 2.5 ¢.c. are required the acidity must be 
reduced by normal sodic hydrate solution. Abbot 
advises using phenolphtalein as the indicator, and 
making the reaction such that 3 c.c. of the decinormal 
solution will neutralize 10 c.c. of the medium. 
6. Boil and clarify with an egg. 
7. Filter first through cotton and iee through 
paper. 
1 Zeitschrift fiir Hyg. und Infek., 1896, Bd, xxi. S. 25. 
