MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



C. Solution A . . . . . . lo ml. 



Solution B . . . . . , 10 ml. 



Citric acid 5% . . . . . . 0-5 ml. 



Note: This solution should be prepared only 

 when required for immediate use. 



D. Sodium thiosulphate 5% aqueous. 



Technique: 



1. Small pieces of tissue are fixed in 20% formalin, and frozen 

 sections are employed. 



2. Rinse thoroughly in distilled water. 



3. Immerse sections in Solution C and leave therein for five to 

 ten minutes. 



4. Plunge sections directly into the sodium thiosulphate solu- 

 tion, without prior washing, and leave therein for five minutes. 



5. Wash thoroughly in several changes of distilled water. 



6. Mount in Aquamount or in Farrant's medium. 



Results: 

 The presence of gold is indicated by a black deposit in the cells. 



SUDAN BLACK 



For lipids (especially those that are not well coloured by 



Sudan III or IV) 



(J. R. Baker's technique) 



Solutions required: 



A. Formaldehyde-saline. 



Formalin (Formaldehyde 40%) . . 10 ml. 

 Sodium chloride 10% aqueous . . 7 ml. 

 Distilled water . . . . . . 83 ml. 



Note: Keep a few pieces of marble chips in 

 the solution to maintain neutrality. 



B. Formalin (Formaldehyde 40%) neutral. 



Note : Keep a few pieces of marble chips in 

 the bottle, 



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