MERCURY AND SILVER 25 



Method of Hand et al. for Mercurous and Mercuric Mercury 



SPECIAL REAGENTS 



Mercurous Reagent. Combine 1 ml. thioglycollic acid with 9 ml. 



glycerol. 

 Mercuric Reagent. Combine 5 g. stannous chloride, 5 g. tartaric 



acid, and 100 ml. glycerol, and heat until clear. Stabilize by adding 



a few grams of metallic tin to the final soln., which should be 



stored in a stoppered bottle. 

 Iodine Reagent. Dissolve 50 g. potassium iodide in 50 ml. distilled 



water; add 70 g. iodine and when it has dissolved, add 95% alcohol 



to make 1 liter. 

 1% Chloroauric Acid. Store in a dark bottle. 

 Control Reagent. Add 5 g. tartaric acid to 100 ml. glycerol. Let 

 stand overnight to dissolve. 



PROCEDURE 



1. Prepare fresh frozen sections of tissue 15 /x thick. 



2. Place sections on slides and allow to dry. 



3. Cover each section with a drop of one of the reagents, depend- 

 ing on the test to be applied, fit on a cover slip, and blot away excess 

 reagent. 



4. Seal edges of cover slip with commercial gold size (adhesive 

 used to hold gold foil on glass) . 



5. After 10 min. examine under a microscope, comparing sections 

 with control reagent to those with other reagents. The sections 

 treated with the mercuric and control reagents remain unchanged 

 for at least 2 weeks. 



Result. The metallic mercury formed in the tissue appears as 

 minute black spheres which may be dissolved by tincture of iodine, 

 or made to lose their glossy surface by forming gold amalgam on 

 treatment with chloroauric acid. In the test for mercurous mercury 

 characteristic yellowish crystals appear after about 5 min., in addi- 

 tion to the mercury globules, when mercuric mercury is also present. 



SILVER 



Particles of reduced silver in tissues may be made more intensely 

 black by treatment with dilute ammonium sulfide solution. 



Okamoto, Utamura, and Akagi (1939) employed the p-dimethyl- 



