MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



Technique: 



1. Fresh tissues are fixed in 70% alcohol for three or four days. 



2. Place sections in alcohol on slides and add a drop of the 

 chloral hydrate solution. 



3. Examine under the microscope and observe concentric 

 layers of inulin crystals, if present. 



4. Add one drop of the thymol solution followed by concen- 

 trated sulphuric acid. 



Results: 



On addition of the last two reagents inulin crystals immediately 

 become red, dissolving after a minute or so. 



Iodine 



Solutions required: 



A. Starch 1% aqueous suspension. 



B. Potassium nitrite 20% aqueous. 



C. Hydrochloric acid cone. . . i ml. 

 Distilled water . . . . . . 19 ml. 



Technique: 



I . Place fresh sections in a watch glass containing 2 or 3 ml. of 

 the starch suspension together with three or four drops each of 

 Solutions B and C. 



Results: 



Iodine is indicated if the starch is coloured blue. 



Iron 



Note: The use of iron or steel instruments in the following 

 technique should be avoided. The section razor, which must, 

 however, be used, should be scrupulously clean. 



Solutions required: 



A. Hydrochloric acid concentrated . . 2 ml. 

 Distilled water . . . . . . 98 ml. 



Potassium ferrocyanide 10% . . 2 ml. 



B. Alum carmine. 



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