Isolation of Specific Pathogenes. 



77 



bacteria. It is also pointed out that the iron oxychloride 

 is bactericidal in 48 hours. 



Drigalski (Drigalski, 1906) has suggested the separa- 

 tion of B. typhi from other bacteria in water through 

 its greater motility. He succeeded in isolating typhoid 

 bacilli from two springs by the following method: five 

 to ten liters of water were allowed to stand for one to two 

 days in tall milk cans at room temperature. Samples 

 were taken from the surface and plated on litmus lactose 

 agar (Drigalski-Conradi medium), the amount of water 

 to be used varying with the contamination. 



The most promising methods for examination of water 

 for B. typhi may be conveniently summarized in the 

 following tabular view adapted from Willson's paper. 



TABULAR SUMMARY. 



Examination 



of water 



for Ty- - 



phoid 



bacilli. 



Isolation 



(1) Filtration. 



(2) Chemical precip. 



f Schiider's process. 

 I Fkker's process. 

 I Alum process. 

 L Muller's process. 



(3) Serum agglutination. 



(4) Enrichment Hoffman and Picker's process. 



(5) Cambier's process. 



Gelatin (Eisner's, etc.) 



Bile-salt agar. 



Glucose and lactose agars. 



(6) Solid media 



Drigalski-Conradi medium. 

 Endo's medium 

 Loeffler's malachite-green 

 agar. 



(Morphological and cultural characters, etc. 

 Identification (Agglutination. 



I r XPfeiffer's, etc. 



Of the comparative advantages of these methods it is 

 still too early to speak with finality. Up to the present 



