CALCIUM 17 



Calcium Sulfate Test for Calcium in Plant Tissue 



SPECIAL REAGENTS 



3% Sulfuric Acid. 

 40% Alcohol. 



PROCEDURE 



1. Fix tissue in acid-free alcohol or acid-free formalin. 



2. Cut sections and bring them down to 40% alcohol. 



3. Add 3% sulfuric acid to sections under cover slip. 



4. Examine for colorless monoclinic needles of calcium sulfate. 



Cretin Color Test for Calcium and Other Minerals 



SPECIAL REAGENTS 



Gallic Acid Reagent. Grind 0.1 g. trioxymethylene (metaformal- 

 dehyde) and 0.2 g. gallic acid in a mortar. Dissolve 0.25 g. of 

 the mixture in 5 ml. boiling distilled water and add 0.5 ml. 

 ammonium hydroxide (18° Baume, or 14% ammonia) ; stir until 

 the solution becomes straw colored. When this reagent turns 

 brown or rose, which it will in a short time, it can no longer be 

 used. 



PROCEDURE 



1. Prepare paraffin sections as usual. Remove the paraffin with 

 xylol and the xylol with chloroform. 



2. After excess chloroform has been removed, add gallic acid 

 reagent. In 10-15 sec, drain off excess reagent and expose slide to 

 air, 



3. Examine when color appears. An eosin counterstain may be 

 applied (Lison, 1936, page 76). 



Result. Calcium gives a blue, barium a bright green, strontium 

 a water blue-green, cadmium a bluish-gi-een, magnesium a yellowish- 

 rose, iron a deep violet-brown, zinc and lead a dull yellow, and 

 silicon a pure yellow color. 



Von Kossa Silver Test for Calcium 



SPECIAL REAGENTS 



5% Silver Nitrate. 



