5. Clear in xylol; mount in balsam.
Stain with lithium carmine either before or after the reaction with ammonium sulphide. Iron is grayish-black to black.
3. Combined or Masked Iron.
1. Treat tissues with Bunge’s fluid (95 per cent alcohol 95 cc., 25 per cent hydrochloric acid 10 cc.) for 1-2 hours at 50-60°C., until inorganic iron is all removed.
2. Place tissues in acid alcohol (sulphuric acid 4 cc. in 100 cc. alcohol 95 per cent.)
5. Wash sections in acid alcohol, then pure alcohol, and finally in distilled water.
6. Transfer to ammonium sulphide (5-60 minutes) or to potassium ferrocyanid and O.5 HCl for 5 minutes.
7. Wash in water.
8. Counterstain in eosin or safranin; wash; dehydrate in absolute alcohol; clear in cedar-oil; mount in benzene balsam. Keep preparations in the dark.
4. Staining of Chromophilic Cells.