494 Typhoid Fever 



flocculent masses collect at the bottom of the tube, forming 

 a flocculent precipitate. The next procedure should be 

 with the tube showing agglutination with the greatest dilu- 

 tion, as the more concentrated preparations carry down not 

 only the typhoid bacilli, but also closely related organisms. 

 After the sedimentation of the agglutinated bacilli is com- 

 plete, the tube is broken at the file mark, and the sediment 

 contained in the short tube washed with two or three changes 

 of distilled water, being allowed to settle each time. This 

 removes many of the organisms not agglutinated. A loop- 

 ful of the washed sediment is transferred to a tube of nutrient 

 broth, and finally from this tube plate cultures are made upon 

 Eisner's or Hiss's media. 



A culture medium for isolating the typhoid bacillus from feces is rec- 

 ommended by Drigalski-Conradi * and by Petkowitsch.f It is made as 

 follows : 



Horse-meat infusion (3 pounds of horse meat 



to 2 liters of water) 2 liters 



Witte's peptone 20 grams 



Nutrose 20 grams 



Sodium chloride 10 grams 



Agar-agar 60 grams 



Litmus solution (Kubel and Tiemann) 260 c.c. 



Lactose 30 grams 



Crystal-violet solution (0.01 per cent.) 20 c.c. 



Before adding the crystal-violet solution render feebly alkaline to 

 litmus (about 0.04 per cent, of pure soda). 



Colon colonies upon this medium appear in fourteen to sixteen hours 

 to be red and opaque. Typhoid colonies blue or violet, transparent 

 and drop-like. 



Gelatin Punctures. When transferred to gelatin punc- 

 ture cultures, the typhoid bacilli develop along the entire 

 track of the wire, with the formation of minute confluent, 

 spheric colonies. A small, thin, whitish layer develops 

 upon the surface near the center. The gelatin is not lique- 

 fied, but is sometimes slightly clouded in the neighborhood 

 of the growth. 



Agar-agar. The growth upon the surface of obliquely 

 solidified gelatin, agar-agar, or blood-serum is not luxuriant. 

 It forms a thin, moist, shining, translucent band with smooth 

 edges and a grayish-yellow color. 



Potato. When a potato is inoculated and stood in the 

 incubating oven, the typical growth cannot be detected 

 even at the end of the second day, unless the observer be 



* " Zeitschrif t f. Hygiene," etc., Bd. xxix. 



t " Centralbl. f. Bakt.," etc., May 28, 1904, Bd. xxxvi, No. 2, p. 304. 



