654 Typhoid Fever 



Wiirtz* and Kashidaf make the differential diagnosis by 

 observing the acid production of Bacillus coli in a medium 

 consisting of bouillon containing i .5 per cent, of agar, 2 per 

 cent, of milk-sugar, i per cent, of urea, and 30 per cent, of 

 tincture of litmus. This is the so-called litmus-lactose-agar- 

 agar. The culture-medium should be blue. When liquefied, 

 inoculated with the colon bacillus, poured into Petri dishes, 

 and stood for from sixteen to eighteen hours in the incubator, 

 the blue color passes off and the culture-medium becomes 

 red. If a glass rod dipped in hydrochloric acid be held 

 over the dish, vapor of ammonium chlorid is given off. The 

 typhoid bacillus produces no acid in this medium, and there 

 is consequently no change in its color. Upon plates with 

 colonies of both bacilli, the typhoid colonies produce no 

 change of color, while the colon colonies at once redden the 

 surrounding medium. 



Rothberger J first employed neutral red for the differentia- 

 tion of the typhoid and colon bacilli. When grown in fluid 

 media containing it, the colon bacillus produces a yellowish 

 fluorescence, while the typhoid bacillus does not destroy the 

 port wine color. Savage and Irons || have made use of the 

 color reaction for the routine detection of the colon bacillus 

 in water. The best adaptation of the method is by Stokes,** 

 who adds it to the various sugar bouillons in the proportion 

 of o.i gram per liter, and uses the medium in the fermen- 

 tation tube. The colon bacillus always ferments the sugars 

 and produces a typical color reaction. 



Hiss ft recommends the use of two special media one 

 for plates, the other for tube-cultures. The first consists 

 of 5 grams of agar-agar, 80 grams of gelatin, 5 grams of 

 Liebig's beef -extract, 5 grams of sodium chlorid, and 10 

 grams of glucose to the liter. The agar is dissolved in the 

 1000 c.c. of water, to which have been added the beef- 

 extract and sodium chlorid. When the agar is completely 

 melted, the gelatin is added and thoroughly dissolved by 



* "Archiv. de med. Experimentale," 1892, iv, p. 85. 



t "Centralbl. f. Bakt. u. Parasitenk.," Bd. xxi, Nos. 20 and 21, 

 June 24, 1897. 



t "Centralbl. f. Bakt.," 1893, p. 187. 



"Journal of Hygiene," 1901, i, p. 437. 



|| Ibid., 1902, n, p. 437. 



** "Jour, of Infectious Diseases," 1904, i, p. 341. 

 ft "Jour, of Experimental Medicine," Nov., 1897, vol. n. No. 6. 



