34 MANUAL OF BACTERIOLOGY. 



have been proposed. In most of those now in use the following 

 solution (Ziehl's carbol-fuchsin) is employed — 



Fuchsin i gram. 



Carbolic acid, pure 5 '^•'^• 



Alcohol lo c.c. 



Distilled water loo c.c. 



The method given below is the one recommended. 

 Method for staining the tubercle bacillus: 



(a) The cover-glass preparation is made, dried, and fixed by 

 passing through the flame three times (see pages 26 and 27). 



(b) The cover-glass, held in forceps or in a watch-crystal, 

 is covered with carbol-fuchsin and heated till the stain begins 

 to give off vapor. The stain is allowed to act for five minutes. 



(c) Wash in water. 



(d) Wash in alcohol containing 3 per cent, of hydrochloric 

 acid one minute, or longer if necessary to remove the red color. 



(e) Wash in water. 



(/) Stain with methylene-blue solution (see page 29) thirty 

 seconds. 



{g) Wash in water. 



(h) Examine in water directly, or after drying and mounting 

 in Canada balsam. Tubercle bacilli take a brilliant red color; 

 other bacteria and the nuclei of cells are stained blue. 



Gabbett's Method. — This method is very popular and widely 

 used on account of its convenience. It is not as reliable as the 

 one just given. 



Gabbett's solution: 



Methylene-blue i to 2 grams. 



25 per cent, watery solution of sulphuric acid 100 c.c. 



(a) The cover-glass preparation is to be made, dried and 

 fi.xed by passing through the flame three times. 



(b) The carbol-fuchsin stain is applied from two to five minutes 

 to the cover-glass, held in forceps or in a watch-crystal; it need 

 not be warmed. 



