SECTION TWO 



GOLD CHLORroE - SUBLIMATE (Cajal) 



For neuroglia fibres; for astrocytes in central nervous 



system 



Solutions required: 



A. Neutral formalin . . . . . . 15 ml. 



Ammonium bromide . . . . 2 gm. 



Distilled water . . . . . . 85 ml. 



B. Gold chloride (brown or yellow) 1% aqueous. 



C. Mercuric chloride 5% aqueous. 



D. Sodium hyposulphite 10% aqueous. 



Technique: 



1 . Fresh pieces of tissue are fixed for two to twenty-one days in 



Solution A. 



2. Frozen sections are cut 15 to 30^ thick. 



3. Rinse in several changes of distilled water. 



4. Immerse sections, flattened out and not lying on top of one 

 another, for three to four hours in a freshly prepared mixture con- 

 sisting of: 



Solution B . . . . • • 5 t^- 



Solution C . . . . • • 5 nil- 



Distilled water . . . . • • 30 ml. 



{Note: 3 ml. of the mixture is required for each 

 section) 



until the astrocytes are stained dark against a relatively light 

 background; the reaction should be controlled by microscopic 

 examination of a section while still wet. 



5. Wash in distilled water; then fix^in Solution D. 



6. Wash thoroughly in tap water. 



7. Dehydrate ; clear and mount. 



Results: 



Astrocytes, black. Nerve cells, red. Nerve fibres, unstained. 

 Background, light brownish purple, or unstained. 



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