BACTERIUM DIPHTHERIA 97 



EXERCISE XLVIII 



BACTERIUM (BACILtUS) DIPHTHERIA {Continued) 



147. Work for this Exercise. — Reexamine all the cultures 

 of Bacterium diphtheria, and describe all the changes which 

 have appeared in them. 



Examine microscopically, in stained cover-glass preparations, 

 the bacteria from the glycerin agar and Loeffler's blood serum 

 cultures. Stain with alkaline methylene-blue, and note espe- 

 cially the way the bacteria stain. Stain a few preparations after 

 Neisser's method (the staining solutions will be furnished) and 

 compare with the methylene-blue stain. 



Note with special care the morphology of the bacteria and 

 make a drawing of a few of them. 



Examine sections of diphtheritic membrane showing diph- 

 theria bacteria, and streptococci (furnished). Reject all cul- 

 tures of diphtheria bacteria. 



Examine very carefully a guinea pig (furnished) which has 

 died from the effect of inoculation with diphtheria organisms. 



Expectorate into a watch-glass vvhich has been wiped 

 with a cloth moistened in a 5% solution of carbolic acid. 

 From this sputum inoculate a tube of bouillon and one of slant 

 agar, and make a series of 2 agar and one of 2 gelatin plate 

 cultures. Use a small loopful of sputum for each tube culture 

 and the same for the first tube in the plate series. 



