MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



Results: 



Zymogen granules, violet; granules of acidophil cells are 

 stained orange-red, while those of basophil cells are violet ; back- 

 ground, brown. 



ORCEIN 

 For elastic fibres and connective tissue 



Solutions required: 



A. Orcein . . . . . . . . i gm. 



70% alcohol . . . . . . 100 ml. 



Heat on a water bath to dissolve; cool; filter; 

 then add : 

 Hydrochloric acid, cone. . . i ml. 



Shake well. 



B. Unna's polychrome methylene blue. 



This should be diluted i : 10 or i : 15 for use. 



1. Fix tissues (any fixative may be employed); dehydrate; 

 clear; and embed. 



2. Paraffin sections are brought down to 70% alcohol in the 

 usual manner; flood with freshly filtered orcein solution, pre- 

 pared as above, and warm gently for ten to fifteen minutes, until 

 the solution thickens. Alternatively, the sections may be stained 

 overnight at room temperature. 



3. Wash thoroughly with 70% alcohol. 



4. Wash thoroughly with distilled water. 



5. Stain in diluted polychrome methylene blue until the nuclei 

 are bright blue to blue-black; the time necessary may be ascer- 

 tained by examining under the microscope at intervals. 



6. Differentiate in 95% alcohol, followed by absolute. 



7. Clear in xylol and mount. 



Results: 



Elastic fibres, deep brown. Nuclei, bright blue or blue to black. 

 Connective tissue, pale brown. 



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