MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



2. Sections are mounted on slides and the mercuric precipitate 

 from the fixative is removed by the standard technique {see 

 page 28). 



3. Bring down to distilled water as usual; then stain from five 

 to fifteen minutes in the thionin solution. 



4. Dehydrate rapidly as otherwise the stain will be removed by 

 the alcohol. 



5. Clear in xylol and mount. 



Results: 



Mucin is metachromatically stained purple; while the basophil 

 granules of the mast cells, Wharton's jelly of the umbilical cord, are 

 purple; and the other tissue constituents are stained in varying 

 shades of blue. 



THIONIN (Ehrlich) 

 For the differential staining of entamoeba in sections 



Solutions required: 



A. Thionin 0-25% aqueous. 



B. Oxalic acid 2% aqueous. 



Technique: 



1. Pieces of tissue are fixed in absolute alcohol and embedded 

 in Celloidin in the usual manner. 



2. Immerse in the thionin solution for three to seven minutes. 



3. Differentiate in the oxalic acid solution for thirty to ninety 

 seconds, controlling by examination under the microscope. 



4. Rinse in water. 



5. Rinse in 70% alcohol. 



6. Dehydrate by rinsing in two changes of 95% alcohol. 



7. Clear in terpineol and mount. 



Results: 



Nuclei of amoebae are stained a rich brown colour, while the 

 nuclei of all other cells are stained blue. 



212 



