MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



Technique: 



1. Sections of material, which have previously been fixed in 

 Flemming's fixative, are stained for two to twenty-four hours with 

 the safranin solution, in a stoppered staining jar. 



2. Differentiate in acid alcohol until colour almost ceases to 

 come out of the sections and microscopic examination shows the 

 chromosomes in metaphase stained clearly with the safranin. 



3. Rinse with distilled water. 



4. Immerse in the gentian violet solution, in a staining jar for one 

 half to three hours, washing with water at intervals and examining 

 under the microscope until the prophase chromatin is clearly 

 stained violet. 



5. Differentiate in the orange G solution for thirty to sixty 

 seconds when pale violet clouds should be given off. 



6. Rinse in absolute alcohol until scarcely any more colour 

 comes out of the sections. 



7. Differentiate in clove oil and while very faint clouds of colour 

 are still coming away, rinse with benzol and mount in balsam. 



Results: 



Chromosomes, red. Nucleoli, red. Metachromatic chromatin, 

 deep purple. Cytoplasm, orange. Spindle, blue-violet. 



Note: The action of this stain should be so precise that in one 

 strand of chromatin the diffused portion will take the violet, while 

 the condensed section should be stained with the safranin. 



WRIGHT'S STAIN 

 For chloroplasts in tissue spreads and for plant cytology 



Note: Valuable for showing cytoplasmic changes in various tissues 

 and cell inclusions. Reveals cytoplasmic differentiations and experi- 

 mental change. The method is generally applicable for cytological 

 work wherever material may be spread (not smeared) and dried rapidly. 

 Produces excellent preparations of chloroplasts. Where cells separate 

 well and where there is neither an excess of water in tissue fluid nor 

 concentrated protein scum, conditions are favourable for a good spread 

 of uninjured cells and an excellent stain. 



Solution required: 

 Wright's stain. 



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