SECTION TWO 

 Technique: 



1. Fix pieces of tissue in solution A overnight. 



2. Embed in celloidin. 



3. Cut sections at 20 to 30JL1, or thinner for special purposes. 



Note: Sections may be stored indefinitely in 70% or 80% 

 alcohol. 



4. Take sections through 50% alcohol to water. 



5. Place 5 ml. of solution B in a 50 ml. beaker and add 0-5 ml. 

 of the sodium nitrite solution, and mix well. 



6. Place the sections in the liquid in the beaker and heat gently 

 to boiling; then immediately turn off the heat and set the beaker 

 aside to cool for two or three minutes. 



7. Wash sections for at least two minutes in each of three lots 

 of about 50 ml. of distilled water. 



8. Mount in glycerine or Kaiser's glycerine jelly, or Aqua- 

 mount, or dehydrate through the usual graded alcohols; then 

 mount in Eurparal or Michrome mountant or Clearmount, or 

 pass through 95% alcohol to origanum oil and mount in D.P.X. 



Results: 



Phenols are indicated by red, pink or orange colorations. In 

 animal tissues the reaction will be due, in the vast majority of 

 cases, to the presence of tyrosine-containing proteins. 



Notes: 



(a) The method is considered to be more rational than Millon's 

 and most of the modifications of Millon's original method, and 

 it produces a more intense coloration. 



(b) The author (Dr. J. R. Baker) found that celloidin sections 

 could be subjected to quite violent treatment without being 

 injured. Boiling, to which paraffin and frozen sections cannot be 

 subjected, intensifies the colour reaction in this technique and 

 does not damage the celloidin sections. 



Reference: Baker, J. R. (1956). 

 L 309 



