220 Hematologic Elements and Related Issues (chap. 16) 



The powder (bulk or capsule) is ground up with methyl alcohol (0.1 

 gm. to 60.0 ml.). The alcohol must be labeled "neutral" and "acetone 

 free." Grind thoroughly in a glass mortar, and pour off supernatant 

 (surface-floating) liquid. If undissolved powder remains, pour back 

 the liquid and grind again. 



Buffer solution, pH 6.4: 



monobasic potassium phosphate 6.63 gm. 



anhydrous dibasic sodium phosphate 2.56 gm. 



distilled water 1000.0 ml. 



procedure: 



1. With wax pencil draw 2 marks across slide delineating region to 

 be stained (length of 40 mm. cover glass). 



2. Cover with 10-12 drops of Wright's stain: 1-2 minutes. 



3. Add an equal amount of buffer: 2-4 minutes. 



4. Rinse in distilled water, 1 or 2 dips. Precipitate deposit on the 

 slide can be avoided by flushing the slide with a pipette, or carry 

 the stain with the slide into the wash water; do not drain it off 

 first. 



5. Blot with 2 sheets of filter paper; press but do not rub. 



6. Allow slide to thoroughly dry before applying cover glass. 



results: 



erythrocytes — pink 

 nuclei — deep blue or purple 

 basophilic granules — deep purple 



eosinophilic granules — red to red-orange, bluish cytoplasm 

 neutrophilic granules — reddish brown to lilac, pale pink cytoplasm 

 granules of monocytes — azure 



lymphocyte granules — larger and more reddish than monocyte gran- 

 ules, sky blue cytoplasm 

 platelets — violet to purple 



comments: 



Precipitate formation can be troublesome; the dark granules obscure 

 the blood cells and are confusing in malarial smears. In addition to 

 poor washing in step 4, another case of precipitate may be evaporation 

 during exposure to undiluted stain. Methyl alcohol is highly volatile 

 and readily lost by evaporation. In dry warm weather use more 

 Wright's, or shorten the time a bit, or cover the slides with a petri 

 dish. Rapid evaporation is easily detected, and more stain can always 

 be added. 



