SECTION TWO 



Technique: 



1. Pieces of tissue no thicker than 3 mm. are fixed from two to 

 eighteen hours in the cobalt nitrate formalin solution, according 

 to the size and nature of the material. 



2. Wash the tissue quickly in a large volume of distilled water. 



3. Immerse in the silver nitrate solution in the dark for thirty- 

 six to forty-eight hours. 



4. Wash quickly in a large volume of distilled water. 



5. Trim the tissue to a thickness not exceeding 2 mm. 



6. Immerse in Solution C (Cajal's Reducer) for two to twenty- 

 four hours in the dark. 



Note: For most soft tissues about four hours will suffice. 



7. Wash in several changes of distilled water. 



8. Dehydrate, clear and embed in paraffin wax in the usual 

 way. 



9. Cut sections up to 8/1 in thickness. 



10. Fix sections to slides; dewax and pass through descending 

 grades of alcohol to distilled water. 



11. Tone sections on slides by immersing in the gold chloride 

 solution for five to ten minutes. 



12. Wash quickly in distilled water. 



13. Fix in 5% sodium thiosulphate (Solution E) for ten to 

 fifteen minutes. 



14. Wash thoroughly in distilled water. 



15. Counterstain with paracarmine for about ten minutes. 



16. Rinse with 90% alcohol, followed by absolute alcohol. 



17. Clear in xylol and mount. 



Results: 



Golgi apparatus stained black while cells are pink or red. 



Reference: Fano, C. Da (1921). 



SILVER NITRATE - HYDROQUINONE 



For the detection of gold in fixed tissues of experimental 



animals 



Notes: 



(a) The following technique must be carried out in the dark- 

 room. 



407 



