Differentiation of Typhoid and Colon Bacilli 653 



Unfortunately, many of the small colonies that develop 

 in Eisner's medium subsequently prove to be those of the 

 colon bacillus, and the method is thus rendered unreli- 

 able. 



Remy* prefers to make an artificial medium approxi- 

 mating a potato in composition, but without dextrin or glu- 

 cose. The composition is as follows : 



Distilled water 1000.0 grains 



Asparagin 6.0 



Oxalic acid 0.5 gram 



Lactic acid 0.15 



Citric acid 0.15 



Disodic phosphate 5.0 grams 



Magnesium sulphate 2.5 



Potassium sulphate 1.25 



Sodium chlorid 2.0 



All the salts excepting the magnesium sulphate are powdered in a 

 mortar and introduced into a flask with the distilled water. Thirty 

 grams of Witte's or Grubler's peptone are then added and the mixture 

 heated in the autoclave under pressure for one-quarter hour. As soon 

 as removed, the contents are poured into another flask into which 120 to 

 150 grams of gelatin had previously been placed. The flask is shaken to 

 dissolve the gelatin, and the contents then made slightly alkaline with 

 soda solution. The mixture is again heated in the autoclave at 1 10 C. 

 for one-quarter hour, then acidified with a one-half normal solution of 

 sulphuric acid, so that 10 c.c. have an acidity neutralized by 0.2 c.c. of 

 one-half normal soda solution. This acidity is equal to 0.5 c.c. sulphuric 

 acid per liter. After shaking, place the flask in a steam sterilizer for ten 

 minutes, then filter. When filtered, verify the acidity of the medium, 

 correcting if necessary. Finally, add the magnesium sulphate, dissolve, 

 dispense in tubes, and sterilize by the intermittent method. 



At the moment of using, put into each tube i c.c. of a 35 per cent, 

 solution of lactose and o.i c.c. of a 2.5 per cent, solution of carbolic acid. 



Upon this medium the colonies of the typhoid and colon 

 bacilli show marked differences. The colon colonies are 

 yellowish brown, the typhoid colonies bluish white and 

 small. Fine bubbles of gas from the fermentation of the 

 lactose often occur about the colon colonies. 



By this method Remy was able to isolate the typhoid 

 bacillus from the stools in 23 cases which he studied. He 

 believes that the constant presence of the typhoid bacillus 

 in the stools of typhoid fever, and its absence from them 

 under all other conditions, is a far more important and 

 valuable method of diagnosis than even the Widal re- 

 action. 



* ''Ann. de 1'Inst. Pasteur," Aug., 1900. 



