90 The Preparation of Microscope Slides 



Single Contrast Stains 



Eosin Y: 



Make up as a 0.5% solution in distilled water. 



Ethyl Eosin: 



Make up as a 0.5% solution in 95% alcohol. 



Both these eosins give very much the same shade and are the conven- 

 tional contrast to hematoxylin or celestine blue B-stained sections. The 

 choice between water and alcohol is a matter of individual preference. 



Another popular contrast stain is: 



Fast Green FCF: 



Make up as a 0.1% solution in 90% alcohol. 



This is sometimes used as a contrast for hematoxylin, for which pur- 

 pose it is not as satisfactory as the eosins, but it is very widely employed 

 as a contrast stain to red nuclei stained either with safranin or carmine. 



Double Contrast Stains. It is no more trouble to use a single solution 

 that will stain different tissues various shades than it is to use a simple 

 solution. Two solutions can be confidently recommended. The first of 

 these is: 



van Gieson's Stain: 



Staining solution 



To 100 ml of a saturated solution of picric acid in water, add 0.05 g of 

 acid fuchsin. 



Stain Is Used as Follows: 



1. Collect sections, with the nuclei stained blue, in tap water. Celestine 

 blue B is the stain of choice. 



2. Stain them from 2 to 5 min in the staining solution. 



3. Give each slide an individual quick rinse in tap water and pass it 

 directly to 96% alcohol. 



4. Keep the slides in motion in 96$ alcohol until they are dehydrated. 



5. Then rinse each section once or twice in absolute alcohol and trans- 

 fer it to xylene. 



6. As soon as the section is clear, mount it in balsam. 



This stain relies for its effect on the fact that muscular tissues retain the 

 yellow color of the picric acid more readily than the other connective 

 tissues. The major objection is that picric acid is soluble to a certain ex- 

 tent in xylene so that the yellow color is gradually extracted. Sections 

 stained by this method and mounted in balsam are rarely of very much 



