MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



Technique: 



I. Sections of fresh tissue are placed in a drop of the above 

 reagent on a sHde and examined under the microscope. 



Results: 



The appearance of fine yellow crystals of potassium cobalt 

 nitrite indicates the presence of potassium. 



Proteins 



Solutions required: 



A. Potassium ferrocyanide . . . . o-8 gm. 

 Acetic acid . . . . . . loo ml. 



B. Ferric chloride aqueous 5%. 



Technique: 



1. Immerse sections of fresh material in Solution A for an hour. 



2. Rinse quickly with 60% alcohol. 



3. Add a few drops of 5% ferric chloride. 



Results: 



A blue coloration indicates proteins. 



Saponin 



Method (a) 



Place a drop of concentrated sulphuric acid on a section of fresh 

 material. 



If saponin is present in the tissue the section immediately 

 assumes a yellow colour which changes to red after about half an 

 hour, and later to violet or bluish green. 



Method (b): 



Solutions required: 



A. Barium hydroxide, saturated aqueous. 



B. Calcium chloride 5%. 



C. Potassium dichromate 10% aqueous. 



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