54 EXAMINATION AND STAINING OF BACTERIA. 



The advantages of this method are that it is generally ap- 

 plicable. Bacteria are not robbed of their color, and the 

 tissue is sufficiently decolorized to render the bacteria visible 

 and to admit of a contrast-stain. 



5. Ziehl-Neelsen's Method. 



The sections are warmed in a solution of carbol-fuchsin for 

 one hour at a temperature of about 45 to 50 C., decolorized 

 for a few seconds in a 5 per cent, sulphuric acid solution, then 

 put into 70 per cent, alcohol, then in absolute alcohol for a few 

 seconds to dehydrate, then in xylol to clear, and mounted 

 on a slide in xylol balsam. 



QUESTIONS. 



What powers of the microscope are necessary for the examination of 

 bacteria ? 



How are bacteria examined alive ? 



How is a hanging-drop preparation made ? 



What is the usual method of staining bacteria? 



What are the most usual stains used for bacteria? 



What is Loeffler's method ? 



Describe the Koch-Ehrlich method. 



What are the usual decolorizing agents used ? 



What is Gram's method ? 



Describe Ziehl's carbol-fuchsin method. 



Describe Gabbett's method. 



Give Welch's method of staining the capsule of bacteria. 



Give Johne's method. 



Give Abbott's method of staining spores. Moeller's method. Fiocca's 

 method. 



Give Loeffler's method of staining flagella. 



Which bacteria require the addition of acid to the mordant in order to 

 stain their flagella? Which require the addition of alkalies? 



Describe Bunge's method of staining flagella. Pitfield's method. 



How would you stain bacteria in tissue? Give Gram's method. Weigert's 

 method. Kuhue's method. Ziehl-Neelsen's method. 



