102 Silver Impregnation II (chap. 15) 



Nassar and Shanklin's Silver Impregnation (1951) S 



fixation: 4 days in: 



formalin 70.0 ml. 



ammonium bromide 14.0 gm. 



distilled water 680.0 ml. 



WASHING, EMBEDDING, and SECTIONING: 



1. After fixation, wash tissue blocks in distilled water plus strong 

 ammonia (50 drops ammonia to 100 ml. water): 10 hours. Keep 

 container covered to prevent escape of ammonia. 



2. Wash in 2 changes of distilled water: 1-2 hours each. 



3. Dehydrate, clear, and embed in paraffin. Cut sections at 10-15 

 microns and prepare slides, 



solution: 



Ammoniated Silver (Lillie, 1946): 



To 1 ml. of concentrated ammonia rapidly add 7-8 ml. of 10% 

 silver nitrate, aqueous. Continue to add 10% silver nitrate drop by 

 drop, shaking each time, imtil only a faint turbidity remains (9-10 

 ml.). Dilute with an equal amoimt of distilled water. 



procedure: 



1. Deparaffinize and hydrate to 3 changes of distilled water: 1-2 

 minutes each. 



2. Sensitize in 5% sodium sulfite (5 gm./lOO ml. water): 2 hours. 



3. Transfer quickly through 3 changes of distilled water. 



4. Impregnate in ammoniated silver solution: 2-5 minutes, room 

 temperature. 



5. Dip in distilled water: 1-2 seconds. 



6. Reduce in 2% formalin (2 ml./98 ml. water): 1 minute. Agitate 

 gently, and change formalin sokuion 3-4 times. 



7. Wash in distilled water: 1 minute. 



8. Tone in gold chloride (1 gm./500 ml. water): few seconds to I 

 minute, or imtil section turns grey. 



9. Fix in 5% sodium thiosidfate (5 gm./lOO ml. water): 1-2 min- 

 lUes. 



10. Wash in running water: 5 minutes. 



11. Counterstain if desired. Dehydrate, clear, and mount. 



results: 



neuroglia — dark grey to black 



