SPECIAL METHODS OF STAINING AND MODIFICATIONS 59 



Behavior of the More Important Bacteria to Gram's Stain. 

 Positive means that the bacteria retain the primary color, or 

 gentian- violet; negative, that they do not. 



Positive. Negative. 



Tubercle bacillus. Colon bacillus. 



Smegma bacillus. Typhoid bacillus. 



Lepra bacillus. Cholera bacillus. 



Anthrax bacillus. Influenza bacillus. 



Tetanus bacillus. Friedlander's bacillus. 



Diphtheria bacillus. Plague bacillus. 



Pneumococcus. Diplococcus intracellularis. 



Streptococcus. Gonococcus. 



Staphylococcus. Koch- Weeks bacillus. 



Cocci of the urethra. Conjunctivitis bacillus of Morax. 



Loffler's Method for Tissues 



Alkaline methylene-blue 5-30 minutes 



i per cent, acetic acid few seconds. 



Absolute alcohol, xylol, Canada balsam. 

 Bacteria dark blue, nuclei blue, cell-bodies light blue. 



To Stain Spores. Since spores have a very firm capsule, 

 which tends to keep out all external agents, a very intensive 

 stain is required to penetrate them, but once this object is 

 attained, it is equally as difficult to decolorize them. 



A cover-glass prepared in the usual way, i. e., drying and 

 passing the specimen through the flame three times, is placed 

 in a watch-crystal containing Ziehl's carbolfuchsin solution, 

 and the same placed upon a rack over a Bunsen burner, where 

 it is kept at boiling-point for one hour, careful to supply fresh 

 solution at short intervals lest it dry up. 



The bacilli are now decolorized in alcohol containing 0.5 

 per cent, hydrochloric acid. A contrast color, preferably 

 methylene-blue, is added for a few minutes. 



