MALARIA 17 



6. Obtaining blood: Clean ear lobe or end of finger with 

 alcohol. Puncture with needle. One drop of blood is 

 mounted one half inch from the end of the slide. Place 

 the end of another slide near the drop of blood at an angle 

 of 30 degrees to 45 degrees with the shorter end of the slide. 

 Draw this slide along until it touches the drop. When the 

 blood has spread along the edge push the slide fairly rapidly 

 toward the other end. A thin film -will result covering about 

 one-half of the slide. Allow the film to dry, then write 

 data directly in it with a lead pencil. 



c. Fixing and staining. (1) Wright's stain: Cover film 

 with a few drops of the stain and allow to remain one minute. 

 Add double the volume of distilled water. After five min- 

 utes, wash, and dry in air. The cytoplasm of the parasite 

 stains blue and the chromatin red. The pigment remains 

 brown, unstained. 



(2) Irishman's stain: Proceed as with Wright's stain. 

 Vary length of periods if necessary. The results are similar 

 to those obtained by the use of Wright's stain. 



(3) Giemsa's stain: Fix in absolute methyl alcohol for 

 5 minutes, wash gently. Stain in one part Giemsa plus 

 ten parts distilled water for ten minutes. Wash. Dry. 

 The results are similar to those obtained by the use of 

 Wright's or Leishman's stains. 



2. Thick films, a. Equipment: Same as for thin films. 



6. Obtaining blood: Same as for thin films, except several 

 drops are obtained near center of slide and spread with the 

 needle over an area of one-half to three-fourths of an inch. 



c. Fixing and staining: Fix and decolorize in 95 per cent 

 alcohol plus 2 per cent HC1 for one-half hour. Wash in 

 running tap water a few minutes. Stain as with thin films. 

 In these preparations more blood cells are present per unit 

 area and hence the presence of parasites is more easily 

 determined. 



