MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



violet to purple granules. Malarial: parasites and Leishmania 

 chromatin, red, cytoplasm, blue. Trypanosomes : chromatin, red. 



Note: The timing of the staining either before or after dilution 

 may be altered to suit individual requirements. 



Staining effects similar to Giemsa are obtained by staining for 

 ten minutes in Wright's stain diluted v^ith four times its volume of 

 distilled v^ater buffered to pH 6-5. 



WRIGHT'S STAIN 

 For demonstrating Trichomonas riedmuller 



Solutions required: 



A. Osmic acid 2% in 0-5% chromic • 



acid. 



B. Wright's blood stain. 



C. Buffer solution pH 7-0. 



Technique: 



1. Fresh, wet smears of the material containing Trichomonas 

 riedmuller are made on slides and exposed to osmic acid fumes for 

 ten to thirty seconds when microscopic examination should show 

 no motility among the organisms. 



2. Cover the smear with five drops of Wright's stain and fifteen 

 drops of the buffer solution, and mix the solutions by gently 

 rocking the slide. Allow this diluted stain to act for two to five 

 minutes. 



3. Pour off excess stain and wash thoroughly with the buffer 

 solution. 



4. Allow the smears to dry thoroughly in the air ; then examine 

 under the oil-immersion objective. 



Results: 



Cytoplasm, blue. Posterior portion of the axostyle, pink. 

 Blepharoplasts, chromatin ring around the posterior part of the 

 axostyle, endoaxostyle granules and nucleus, dark purple. The 

 cytostome appears as a clear area at the anterior extremity of the 

 body of the organism. The anterior flagella and those bordering 

 the undulating membranes are stained pink. 



Adapted from J^. Parasitology, 5, 473-4, 1938, H. M. Stewart. 



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