44 PRACTICAL BACTERIOLOGY. 



DEMONSTRATION XVII. 



Cultures of Uacillus Typhosus and Bacillus Coli Communis — Serum 



Diagnosis of Typhoid Fever — Cultures of Bacillus Pestis 



Bubonicoe, Bacillus Icteroides and 



Bacillus Mallei. 



1. Make and compare hanging drop preparations 

 from the peptone tubes of Bacillus typhosus and Bacil- 

 lus coli communis. 



2. Examine the peptone cultures of Bacillus typhos- 

 us and Bacillus coli communis for indol, adding to each 

 tube 1 cc. of a .01% fresh solution of potassium nitrite, 

 before the addition of the sulphuric acid. 



Bacillus coli communis gives the indol reaction. 



3. Make cover glass preparations of Bacillus 

 typhosus and Bacillus coli communis. Stain in anilin 

 gentian violet or in Loeffler's methylene blue. 



The serum diagnosis of Typhoid Fever and 

 Typhoid Bacilli. 



In the blood serum of animals immunized against 

 Bacillus typhosus, and also, at an earlier or later date, 

 in the blood of persons with Typhoid fever, there are 

 present certain constituents which possess the specific 

 property of agglutinating liquid cultures of Typhoid 

 bacilli. The phenomena noted microscopically are loss 

 of motility of the bacilli and their aggregation in 

 clumps. In tube experiments, we have precipitation of 

 the contained bacilli. For the proper application of 



