36 GENERAL BACTERIOLOGY LESSON 



Concentrated aqueous solution of 



methylene-blue . . .50 cc. 

 Eosine ..... -5 gramme 

 Absolute alcohol . . 70 cc. 



Distilled water . . . 130 cc. 



(a) Keep the section in absolute alcohol for five minutes. 



(b) Transfer it to the stain for four to twelve hours. 



(c) Wash it in water till the section appears pink, and 

 shows hardly any trace of blue. 



(d) Dehydrate, clear, and mount in the usual manner. 



Examine with low and high powers. The bacilli are 

 stained blue and the tissues pink. 



(3) Double staining with picrocarmine and Loffler's methylene- 

 blue. 



(a) Place the section in alcohol for half a minute. 



(b) Then wash it in water and place it in a solution of 

 picrocarmine and water (equal parts) for ten to twenty 

 minutes. 



(c) Wash it in spirit, to which a few drops of l^dro- 

 chloric acid have been added, for half a minute to one 

 minute. 



(d) Wash it in water. 



(e) The sections are now stained red, and should be 

 placed in methylene-blue and treated as described before. 



(4) Staining of sections by Gram's method. 



(a) Place the section in alcohol for half a minute. 



