SECTION THREE 



HAEMATOXYLIN - BISMARK BROWN 

 For Phloem tissues of woody plants 



Solutions required: 



A. Iron alum 2% aqueous. 



B. Haematoxylin i% aqueous. 



C. Bismark Brown 1% aqueous. 



Technique: 



1. Immerse sections in solution A for ten to twenty minutes. 



2. Drain off excess solution; then wash in six or seven changes 

 of distilled water. 



3. Cover the preparation with solution B, placing the slide on 

 the microscope stage. 



4. Observe the progress of the stain under the low power 

 objective and when the required depth of staining has been at- 

 tained, pour off excess stain and rinse quickly in distilled water. 



5. Rinse again with two or three changes of distilled water. 



6. Immerse the preparation in solution C in a staining tube or 

 jar for three to four hours, depending on the thickness of the 

 sections. 



7. Remove excess stain by washing well with water. 



8. Wash with 50% alcohol, followed by 70% alcohol. 



9. Wash with 90% alcohol. 



10. Wash with two changes of absolute alcohol. 



11. Clear in xylol, and mount in Cristalite or Clearmount or 

 Canada balsam in xylol. 



Results: 



Stone cells of hard woods are stained cherry red; bast fibres are 

 brilliant orange, whilst the ray cells and other parenchymatous 

 tissues are a chestnut brown, and the middle lamellae dark blue. 

 The bast fibres, parenchymatous tissues, and middle lamellae of 

 Coniferophyta are stained as indicated, but the stone cells turn a 

 vivid burnt orange. 



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