SECTION TWO 



B. Dichrotnate calcium 



Potassium dichromate . . . . 5 g"^- 

 Calcium chloride, anhydrous, io% 



aqueous . • • • . . lo ml. 



Distilled water 90 ml. 



C. Acid haematein 



Sodium iodate, 1% aqueous . . i ml. 

 *Haematoxylin, 1% aqueous . . 5 ml. 



Distilled water 43 "^1- 



Shake or stir well; then heat to boiling point; cool 



and add: 



Glacial acetic acid . . • • i ml. 



* Note: The 1% haematoxylin should not be more 

 than seven to fourteen days old. 



The acid haematein (solution C) should be pre- 

 pared in a quantity sufficient only for one day's use, 

 as it does not keep for more than a few hours. 



D. Borax-ferricyanide diffei-entiator 

 Potassium ferricyanide, 0-5% 



aqueous . • • • • • 5° m^- 



Borax, 0-5% aqueous . . • • 50 ml. 



Keep solution D in a dark bottle. 



Technique: 



1. Fk small pieces of tissue in solution A for sk to eighteen 

 hours. 



2. Transfer to the dichromate-calcium (solution B) and leave 

 therein for eighteen hours at 22° C. 



3. Transfer to a fresh lot of dichromate-calcium and leave 

 therein for twenty-four hours at 60° C. 



4. Wash well in distilled water. 



5. Cut frozen sections at lo/x. 



Note: If desired, tissues can be first embedded in gelatine (as 

 in the Sudan black technique, page 424). 



6. Mordant in dichromate-calcium (solution B) for one hour 

 at 60° C. 



7. Wash well in distilled water. 



8. Stain in the acid haematein solution for five hours at 37° C. 



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