Silver J inprcgiKiliun for Reticulum 185 



dissolved. Add 5 ml. of 3.1% sodium hydroxide (3.1 gm./lOO ml. 

 water). Barely dissolve the resulting precipitate with a few drops of 

 ammonia. Make the solution up to 500 ml. with distilled water. Use 

 immediately. Glassware must be acid-clean. 



Reducing solution: 



distilled water 50.0 ml. 



formalin 0.5 ml. 



uranium nitrate, 1% (above) 1.5 ml. 



Make up fresh each time. 

 Gold chloride: 



gold chloride stock solution (1 gm./lOO ml. 



water) 10.0 ml. 



distilled water 40.0-80.0 ml. 



procedure: 



1. Deparaffinize and hydrate slides to water; remove HgCU. 



2. Wash thoroughly in distilled water. 



3. Treat with phosphomolybdic acid: 1 miniue. 



4. Wash in riuining water: 5 minutes. 



5. Treat with uranium nitrate: 5 seconds or less. 



6. Rinse in distilled water. 



7. Impregnate with ammoniacal silver nitrate solution: 1 minute. 



8. Dip quickly in 95% alcohol and immediately into reducing solu- 

 tion: 1 minute. 



9. AV^ash in distilled water: 2-3 minutes. 



10. Tone in gold chloride until yellow colors turn purplish grey. 



11. Brief rinse in distilled water. 



12. Fix in sodium thiosulfate, 5% (5 gm./lOO ml. water): 3-5 

 ininutes. 



13. Wash in running water: 5 mintites. 



14. Counterstain if desired. 



15. Dehydrate, clear, and mount. 



results: 



reticulum fibers — black 



other tissue elements — depends on counterstain 



comments: 



Phosphomolybdic acid replaces potassium permanganate as an oxi- 

 dizer; the former shows less tendency to loosen sections. Sensitization 

 with uranium nitrate reduces the time and eliminates the heat re- 



