MEDICAL AND BIOLOGICAL STAINING TECHNIQUES 



Technique: 



1. Slices of the material 2 to 5 mm. thick are fixed in 10% 

 formalin ; then transferred to Solution A for four to seven days. 



2. Wash in running water for several hours; then dehydrate 

 and embed in Celloidin, L.V.N, or in paraffin wax, or cut frozen 

 sections (in which case 2% ammon. bromide should be added to 

 the formalin fixing solution). 



3. Sections 10 to 20 fi in thickness are stained twenty-four to 

 forty-eight hours in a freshly prepared mixture consisting of i vol- 

 ume Solution B and 9 volumes Solution C. 



4. Immerse for one half to three minutes in Solution D ; then 

 rinse in distilled water. 



5. Differentiate in Solution E for one half to three minutes or 

 until the white matter is blue-black, and the grey matter almost 

 colourless. 



6. Counterstain with safranin 1% aqueous, if desired, for one 

 half to two hours according to thickness of sections. 



7. Wash thoroughly in water. 



8. Dehydrate ; clear and mount. 



Results: 



Myelin sheaths, blue-black. Myelinated fibres, black or blue- 

 black. Grey matter, white or slightly yellow. Other structures, 

 unstained (unless a counterstain has been used). 



WOOL GREEN - HAEMATOXYLIN - PONCEAU S 

 For connective tissue and muscle 



Solutions required: 



A. Picric acid, saturated in 70% alcohol. 



B. Weigert's haematoxylin A. 



C. Ponceau S 1% in 1% acetic acid aqueous. 



D. Weigert's haematoxylin B. 



E. Wool Green S 1% in 1% aqueous acetic acid. 



F. Acetone and xylol, equal volumes of each. 



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