4QO Typhoid Fever 



tion the medium receives the addition of i per cent, of 

 potassium iodid; then it is filled into tubes and sterilized 

 like the ordinary culture media. 



When water or feces suspected of containing the typhoid 

 bacillus are mixed in this medium and poured upon plates, 

 no bacteria develop well except the typhoid and colon 

 bacilli. 



These, however, differ markedly in appearance, for the 

 colon colonies appear of the usual size in twenty-four hours, 

 at which time the typhoid bacillus, if present, will have 

 produced no colonies discoverable by the microscope. 



It is only after forty-eight hours long after the colon 

 colonies have become conspicuous that little colonies of 

 the typhoid bacillus appear as finely granular, small, round, 

 shining, dew-like points, in marked contrast to their large, 

 coarsely granular predecessors. Unfortunately, many of 

 the small colonies that develop in Eisner's medium sub- 

 sequently prove to be those of the colon bacillus, and the 

 method is thus rendered unsatisfactory. 



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 grams 



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 pep- 

 tone are then added and the mixture heated in the auto- 

 clave under pressure for one-quarter hour. As soon as 

 removed, the contents are poured into another flask into 

 which 120-150 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 mix- 

 ture is again heated in the autoclave at 110 C. for one- 

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



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



