SECTION TWO 



Technique: 



1. Fix the material in one of the above fixatives (I, II, III, IV 

 or V) and embed in paraffin wax. 



2. Fix sections to sUdes and remove paraffin wax with xylol. 



3. Rinse with two changes of absolute alcohol. 



4. Wash with 90% followed by 80% alcohol. 



5. Immerse slides directly into solution B for one to one and a 

 half hours at 50 to 60° C. in an oven. 



6. Rinse quickly in two changes of distilled water. 



7. Reduce by immersing in solution C for three minutes at 

 25 to 30° C, agitating the slides gently for the first two minutes. 



8. Wash thoroughly in four or five changes of distilled water. 



9. Wash with 50% followed by 70% and 80% alcohols. 



10. Examine under the microscope while the preparation is still 

 wet and if it is found that the staining is not complete, repeat step 

 5 using the original urea-silver nitrate solution and reducing the 

 time to ten to fifteen minutes ; then repeat steps 6, 7, 8 and 9. 



11. Rinse with 95% alcohol. 



12. Dehydrate with two changes of absolute alcohol. 



13. Clear in xylol and mount. 



Results: 



Nerve fibres are stained from brown to black, while nerve end- 

 ings are usually black, and nerve cells from yellow to brown. The 

 background is usually yellow, but its appearance depends upon 

 the kind of tissue and the fixative employed. 



Reference: Ungewitter, L. H. (195 1), Stain Tech., 26, p. 75. 



VERHOEFF'S STAIN 

 For elastic fibres, nuclei and collagen 



Solutions required: 



A. Haematoxylin 5% in absolute 



alcohol . . . . . . . . 20 ml. 



218 



