IRON 21 



sections, brought down to water, with the conversion reagent for 

 24-36 hr. at 35°. 



4. Wash in 90% alcohol followed by distilled water. 



5. Place in the organic iron reagent for not over 5 min. 

 6—7. Same as 4-5 for inorganic iron. 



Result. The iron appears blue. 



Humphrey Dinitrosoresorcinol Test for Iron 



SPECIAL REAGENTS 



30% Ammonium Sulfide. 



Saturated Aqueous Dinitrosoresorcinol or a 3% soln. in 50% alcohol, 

 (A few days aging improves the reagent; it is stable.) 



PROCEDURE 



1. Prepare formalin-fixed paraffin sections. 



2. Remove paraffin; bring down to water, and place in the am- 

 monium sulfide solution for 1 min. 



3. Rinse in distilled water and place in the dinitrosoresorcinol 

 reagent for 6-20 hr. depending on the depth of the brown background 

 desired. 



4. Wash in water or dilute alcohol depending on whether an 

 aqueous or alcoholic reagent was used. 



5. Pass through alcohols, carboxylol and xylol, and mount in 

 balsam. 



Result. The iron appears bright dark green against a reddish or 

 rich brown background. For organic iron introduce steps 3-4 in 

 Prussian blue procedure ( see page 20) between steps 1 and 2 above. 



Thomas and LavoUay Hydroxyquinoline Test for Iron 



SPECIAL REAGENTS 



Hydroxyquinoline Reagent. Dissolve 2.5 g. 8-hydroxyquinoline in 

 4 ml. glacial acetic acid with the aid of gentle warming. Quickly 

 add distilled water to bring volume to 100 ml. and filter the soln. 



25% Ammonium Hydroxide. 



PROCEDURE 



1. Fix tissue in alcohol, neutral formalin, or trichloroacetic acid 

 soln. 



2. Prepare frozen or paraffin sections as usual. 



