Removal of Pigments 24?) 



Morton ef a I. (1960) 



fixation; any general fixative, or fresh frozen sections. 



solution: 



sodium-2,6-dichlorobenzenone-indophenol .... 0.1 gm. 



50% ethyl alcohol 100.0 ml. 



Prepare just before use. Filter and add: 



1% hydrochloric acid (I ml./99 ml. water) until color of solution 

 is red (approximately 1:5) or until pH is 2. 



procedure: 



1. Deparafhnize and hydrate slides to water. 



2. Treat with HCl-indophenol: 5 minutes. 



3. Dip in tap water several times until background loses color. 



4. Mount in glycerol jelly or Apathy. 



results: 



lipofuscins — red 



erythrocytes — blue 



other tissue elements — colorless to blue or slight pink 



comments: 



Avoid alcohol; it removes color immediately. Stain fades in about I 

 day. 



Removal of Pigments 



Melanin pigment (pearse, 1953) 



This will appear as brown, greyish, or almost black granules. 

 Permanganate Method of Removal 



1. Hydrate slides to water. 



2. 0.1% potassium permanganate, aqueous: 12-24 hours. 



3. Wash in running water: 5 minutes. 



4. 1% oxalic acid, aqueous: 1 minute. 



5. Wash in running water: 10 minutes, and proceed to stain. 



Performic or Paracetic Acid MetJiods of Removal 



Lillie {1954 B) claims that the above method can be unpredictable 

 and that the best bleaching is done with performic and paracetic acid: 

 1-2 hours: 



performic acid: to 8 ml. of 90% formic acid, aqueous, add 31 ml. 

 of 30%, H2O1; (undiluted reagent) and 0.22 ml. of concentrated 



