248 Cytoplasmic FAements (chap. 18) 



solutions: 



Methenamine silver solution: 



silver nitrate, 5% aqueous (5 gm./lOO ml. wa- 

 ter) 5.0 ml. 



methenamine, 3% aqueous (3 gm./lOO ml. wa- 

 ter) 100.0 ml. 



Mix and shake. Precipitate which forms redissolves. Keep in cool 

 dark place. Good for several months. 



Buffer solution, pH ±9.0: 



M/5 boric acid (12.368 gm./lOOO ml. water) . . 20.0 ml. 

 M/20 borax (19.071 gm./lOOO ml. water) 80.0 ml. 



Working" solution: 



methenamine silver solution 30.0 ml. 



buffer solution 8.0 ml. 



procedure: 



1. W^hen mounting sections on slides, float on water only a fe^v^ sec- 

 onds or try 95% alcohol. 



2. Deparaffinize and run slides down to 95% alcohol. 



3. Treat in methenamine silver working solution, preAvarmed to 

 37°C: 30 minutes. 



4. Rinse in distilled water. 



5. Fix in sodium thiosulfate, 5% aqueous: 3 minutes. 



6. Wash in running water: 5 minutes. (Gold toning optional) 



7. Counterstain if desired. 



8. Dehydrate, clear, and mount. 



results: 



uric acid crystals — black crystalline fine granules 



Enterochromaffin {EC) Cell Stain 



Fontana Method (culllng, 1958), and Methenamine Silver 

 (gomori, 1952; 1954B) 



fixation: Zenker formol preferred; do not use alcohol — it dissolves 

 argentaffin granules. 



During embedding, do not expose to paraffin longer than 30 minutes. 



solutions: 



Silver solution A: (Fontana Method) 



To 25 ml. of 10% silver nitrate (10 gm./lOO ml. water) add ammonia 



