STAINING, PRACTICAL AND THEORETICAL 



Rapid method for spirochaetes : 



1. Air-dried films are fixed by heat by drawing through the 

 flame. 



2. Allow the slide to cool; then flood the slide with a freshly 

 prepared mixture consisting of lo drops of Giemsa stain to lo ml. 

 distilled water. 



3. Heat the shde gently till steam rises ; allow to cool for about 

 twenty seconds ; then pour oflF the stain and repeat the process five 

 or six times. 



4. Wash with distilled water; blot dry and mount. 



Slow method for films, for demonstrating spirochaetes, 

 trypanosomes, etc. : 



1. Air-dried films are fixed for three minutes in pure methyl 

 alcohol. 



2. A fresh mixture is prepared by diluting Giemsa stain in the 

 proportion of 10 drops of stain to 10 ml. distilled water. The slide 

 is then placed in a staining jar and left to stain in the diluted 

 Giemsa for sixteen to twenty-four hours ; if a staining jar is not 

 available, place a piece of thin glass rod in a Petri dish ; lay the 

 slide with one end resting on the rod, film face downwards, in the 

 Petri dish, and pour in sufficient diluted stain to cover the film; 

 then line the Petri dish lid with two sheets of moist filter paper to 

 prevent evaporation, and cover the preparation. 



3. Wash with distilled water ; blot and dry. 



Method for bacterial smears, throat exudate, etc. : 



1. Thin, air-dried, unfixed smears are covered with undiluted 

 Giemsa stain for thirty seconds ; then a quantity of distilled water, 

 equivalent to five to ten times the volume of stain used, is added 

 and mixed with the stain by gently rocking the slide. 



2. Allow the diluted stain to act for two to five minutes; then 

 wash with distilled water; blot and dry. 



Thin blood film method : 



I. Air- dried films are fixed for five minutes in pure methyl 

 alcohol ; then blotted and dried in air. 



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