CHAPTER XV 

 THE DIPHTHERIA GROUP 

 MEMBERS 



Bacillus diphtheriae. 

 B. pseudodiphthericus. 

 B. xerosis. 



Use great caution in handling members of this group. 

 Inoculate agar-slants from stock-cultures of B. 

 diphtheriae and B. pseudodiphthericus. 



1 . Routine study. Stain B. diphtheriae with Loeffler's 

 methylene-blue instead of gentian-violet. The staining 

 may be facilitated by the application of mild heat. 

 Observe particularly the peculiar effects of the staining 

 process, and make accurate sketches of what yon see 

 under the microscope. 



2. Special study A. Neisser's method of staining to 

 demonstrate the granules in the bacilli: 



a) Prepare two solutions. 



SOLUTION I 



Methylene-blue i g. 



Dissolve in alcohol 96$ 20 c.c. 



Add distilled water. . . 950 c.c. 



Glacial acetic acid 50 c.c. 



SOLUTION II 



Bismarck brown 2 g. 



Distilled water 1000 c.c. 



b) Prepare a film in the usual manner from a culture 

 of B. diphtheriae on blood-serum (furnished). 



c) Stain in Solution I for 5 to 6 seconds. 



d) Wash in water. 



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