450 BACTERIOLOGY. 



intuit 1 with Drigalski-Conradi agar, or 500 c.c. of the 

 water may be precipitated with typhoid immune .serum 

 according to the method of Altschuler and incubated 

 attain for three hours and then plated, or 500 c.c. may 

 be precipitated by the chemical-mechanical method of 

 Ficker. 1 The sediment in the portion of water which 

 has been precipitated in this manner is distributed over 

 a series of three or four plates of the Drigalski-Conradi 

 medium. Subsequently the sediment is diluted three- 

 or fourfold and distributed over another series of plates. 

 By these methods Hoffmann and Ficker succeeded in 

 isolating bacillus typhosus when present in a mixture 

 of 1 : 51,867 water bacteria. 



v. Jaksch and Rau l employed the method of Hoff- 

 mann and Ficker for the isolation of bacillus typhosus 

 from the water supply of the city of Prague, and suc- 

 ceeded in finding bacillus typhosus in three out of five 

 samples examined, one of which was taken from a tap 

 in the hospital, while the others were taken from the 

 Moldau, at different points along the city front. The 

 two negative samples were derived from points along 

 the upper portion of the stream where there was less 

 opportunity for the water to become polluted. The 

 demonstration of the presence of bacillus typhosus in 

 these samples of water was substantiated by all the 

 known cultural methods as well as by the agglutination 

 test, using for the latter purpose the serum of a highly 

 immunized rabbit which agglutinated the bacteria iso- 

 lated from the water in the proportion of 1 : 10,000. 

 Higher dilutions were not made. 



1 Ficker: Hygienische Ruudschau, 1904, Bd. xiv., S. 7. 



2 v. Jaksch and Eau : Centralblatt fur Bacteriologie, 1904, Bd. xxxvi., 



S. 584. 



