Hematoxylin Slainitig Procedures 133 



bluing action. Then use Scott's soliuion (step II), a couple of drops 

 of ammonia in a final wash, or a weak solution of sodium bicarbon- 

 ate, to insure the alkaline condition. In the regressive method (be- 

 low) the same applies, and as a precaution against neutralization 

 caused by carrying one solution over into the other (step 5), after 

 several exchanges of slides, add a drop or two of acid and base to 

 them. If there is any pinkness left in the nuclei, they are not ade- 

 quately blued. 



Regressive Method 



procedure: 



1. Deparaffinize and run slides down (hydrate) to water, removing 

 HgClo if present. 



2. Stain in Delafield's hematoxylin, until slides are well overstained: 

 15-20 minutes. 



3. Wash in running water: 3-5 minutes. 



4. Transfer to 70% alcohol. 



5. Destain in 0.5^^ (app.) HCl (2-3 drops in 60.0 ml. of 70% alcohol) 

 few seconds. Remo\'e to 70%, alcohol with drop of ammonia added 

 until sections turn blue. Examine under microscope. If nuclei are 

 too dark, repeat above procedure. When nuclei stand out sharply 

 blue against colorless background, blue slides thoroughly in alka- 

 line solution: 3-5 minutes. 



6. Transfer to 70% alcohol. 



7. Counterstain. 



8. Dehydrate as for progressive staining. 



9. Clear and mount. 



results: 



nuclei — deep blue, sharper than in the progressive method 

 other elements — colors of counterstain 



Mayer's Hematoxylin 



fixation: any general fixative or one specific for nuclear detail. 



solutions: 



Hematoxylin, page 125. 

 Counterstains, page 129. 



procedure: 



1. Deparaffinize and run slides down (hydrate) to water, removing 

 HgCl. if present. 



