THE COLON, TYPHOID AND DYSENTERY BACILLI 347 



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. It 

 is essential that the primary plate cultures should be made upon 

 some mediuna which will specially favor the detection of colonies 

 of this organism. Several different technical methods have been 

 developed of which the most important are those of Krumwiede 

 and his coworkers and of Russell and his followers at the Army 

 Medical School. Krumwiede^ and Pratt employ an agar contain- 

 ing brilliant green, which exercises a relative inhibition upon most 

 of the other fecal bacteria, thus favoring the development and 

 detection of B. typhosus. Russell's method as employed in the 

 U. S. Army utilizes Endo's medium.^ The fecal material is mixed 

 with broth to form an opaque suspension. A drop of this sus- 

 pension is transferred to the surface of an Endo plate and is spread 

 over the surface by means of a sterile bent glass rod. After in- 

 cubation at 37° C. for 24 hours the tj^hoid, paratyphoid and dys- 

 entery bacilli appear as small, clear, almost colorless, transparent 



'■ Krumwiede, Pratt and McWilliams, fourn. Infectious Diseases, 1916, 18, i. 



^ For Endo's medium a stiflE lactose agar is prepared containing Liebig's extract 

 S grams, salt s 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 are 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 approximately 20 drops of a freshly 

 prepared solution of sodium sulphite, pr just sufficient to decolorize the fuchsin 

 The amounts of fuchsin and of sulphite may be altered to suit different lots of 

 medium and it is well to test out several different quantities upon known cultures 

 of typhoid, paratyphoid and various dysentery bacilli before deciding upon the 

 exact amounts of fuchsin and of sulphite of particular samplei, to be used. Both 

 of these substances, but especially the sulphite, are subject to variation in com- 

 position as they are obtained in the market. The material is well mixed and poured 

 into 8 or ro Petri dishes, allowed to solidify and dried in the incubator to remove 

 water from the surface before use. Large Petri dishes, 15 cm. in diameter, are 

 preferable. . 



