Nissl Substance 195 



5. Mordant in 5% sodium carbonate (5 gm./lOO ml. water): 1 hour. 

 Tissue may remain in this solution 5-6 hours with no ill effect. 



6. Impregnate in silver solution: 3-5 minutes or tnitil sections turn 

 a smooth grey when transferred to reducer. Try single sections 

 at 3 minutes, 5 minutes, or longer. 



7. Reduce in 1% formalin. Agitate during reduction. 



8. Wash in distilled water. 



9. Tone in gold chloride (1 gm./500 ml. water) until bluish grey. 



10. Fix in 5% sodium thiostilfate, 3 mintues. 



11. Wash in running water: 5 minutes. Dehydrate, clear, and mount. 



results: 



oligodendroglia and microglia — dark grey to black 



comments: 



If only the oligodendroglia are to be shown, cut fixation time down 

 to 2 days. Long fixation tends to increase the staining of the microglia 

 and astrocytes. 



Procedure for oligodendroglia: 



1. Follow fixation by treatment with 95% alcohol: 36 & 48 hours. 



2. Wash, freeze, and cut sections. 



3. Stain in a stronger silver solution by diluting the above solution to 

 only 45 ml.: 15 mintites or more, until the sections begin to turn 

 brown. 



4. Wash for a few seconds in distilled water. 



5. Reduce with agitation, wash, and tone as above. 



6. Dehydrate, clear, and mount. 



results: 



oligodendroglia — black 



Nissl Substance 



Cresyl Violet (keller, 1945) S 



Nissl substance is characteristic of fixed nerve cells. It is found in a 

 granular form distributed through the cytoplasm and stains bril- 

 liantly with basic aniline dyes. 



fixation: Bouin's recommended; others are satisfactory; Zenker's not 

 recommended. 



sectionlng: Paraffin method, 10 microns; thinner sections of no ad- 

 vantage. 



