334 SPECIFIC MICRO-ORGANISMS 



(200 c.c. of broth to 2 c.c. of blood) as well as inoculating tubes of 

 bile and the usual agar plates; by cultures from the rose spots, 

 and by cultures inoculated with duodenal fluid. These methods 

 are likely to be successful very early in the disease. Later it 

 is well to make cultural examination of the feces and urine, 

 especially just before discharging a recovered patient. 



The detection of B. typhosus in feces requires special care. 

 Russell recommends plating the feces on Endo's medium, 1 fishing 

 of the promising colonies to a slant of his double-sugar medium, 2 

 inoculating both as a streak and stab, and then making the agglu- 

 tination test with known serum upon the typical cultures in the 

 double-sugar medium. The examination is thus completed in 

 two or three days. 



The specific antibody ordinarily sought in the blood is the 

 typhoid agglutinin. A few drops of blood in a Wright's capsule 

 suffice for the microscopic test (see page 211). A young active 

 culture (broth three hours) of a known B. typhosus is used, and 

 the serum is tested in dilutions of 1:20, 1:40 and 1:80, observed 

 for an hour. Normal serum rarely shows any clumping in any 

 of these dilutions at the end of an hour. This agglutination test 

 is of little or no value if the patient has received typhoid vaccine 

 within a year. 



Transmission of the disease takes place in a variety of ways. 

 To the best of our knowledge, the typhoid bacilli come only from 

 human individuals infected with them. Some of these actually 



1 For Endo's medium a stiff lactose agar is prepared containing Liebig's extract 

 5 grams, salt 5 grams, pepton 10 grams, lactose 10 grams and agar 30 grams in 1000 

 c.c. of water. This is sterilized in flasks containing 100 c.c. each. When needed 

 the contents of a flask is liquefied, enough sodium hydroxide is added [to make the 

 reaction 0.2 per cent acid to phenolphthalein and to it are then added 10 drops of 

 saturated alcoholic solution of basic fuchsin, and 20 drops of a freshly prepared solu- 

 tion of sodium sulphite. The material is well mixed and poured into 8 or 10 Petri 

 dishes, allowed to solidify and dried in the incubator to remove water from the sur- 

 face before use. Fecal material is spread by means of a bent glass rod over the sur- 

 face of several plates in succession. 



2 The double-sugar medium is a 2 to 3 per cent agar, neutral to litmus, to which 

 has been added i per cent lactose and o.i per cent glucose. On this medium B. 

 typhosus does not change the color when it is growing on the surface, but produces 

 a red (acid) color about the stab. See Russell, Journ. Med. Rsch., 1911, Vol. XX, 

 pp. 217-229. 



