Stains and Staining 83 



form the dye is unstable. Exposure to alkali changes the dye to a dark- 

 blue stable form. 



Note: Make up the stain by first dissolving the hematoxylin in the acid 

 and alcohol. Then dissolve 1 g of ammonium alum in the water and add 

 this together with the glycerin. Shake well and add about 10 g of am- 

 monium alum to the bottle. Allow to ripen some months, making sure that 

 there are always a few crystals of ammonium alum in the bottom of the 

 bottle. This stain keeps well for about 10 years and works best after it is a 

 year old. Large laboratories, therefore, should make up half a gallon 

 every 2 or 3 years in order to have well-ripened material always in stock. 



Bluing solution 



0.1% sodium bicarbonate in tap water 



Stain Is Used as Follows: 



1. Accumulate the sections in 90 per cent alcohol. 



2. Place each slide for Y 2 to 2 min in the staining solution. 



3. Remove each slide and drop 90 per cent alcohol on it either from a 

 drop bottle or a pipette until the excess stain has been removed. 



4. Transfer the slides directly to alkaline tap water until blue. 



Note: If the sections are taken directly from water to stain or from 

 stain to water, a diffuse stain that is very difficult to differentiate will 

 result. 



Delafield's Alum Hematoxylin 



Note: Dissolve the dye in the alcohols and the alum in the water. 

 Mix the two solutions and ripen for some months. 



