STAINING, PRACTICAL AND THEORETICAL 



Technique: 



Note: It is advisable to protect preparations with celloidin coating (method, 



P- 509)- 



Any fixative may be used, but alcohol was recommended by Hotchkiss (1948) 

 for glycogen and other easily soluble polysaccharides. If the material is fixed 

 in alcohol, then solution B should be used instead of solution A in the following 

 technique. 



1. Press sections on to slides without the use of glycerine 

 albumen. 



2. Pass sections or smears into alcohol as usual. 



3. Coat with celloidin, if desired. 



4. Immerse preparations in solution A or B for five minutes. 



5. Pour off excess solution A or B. 



6. Wash well with 70% alcohol. 



7. Immerse in reagent C for five minutes. 



8. Wash well with 70% alcohol. 



9. Immerse in solution D for fifteen to forty-five minutes. 



10. Wash with two or three changes of solution E. 



11. Wash thoroughly with running water for 5-10 minutes. 



12. Dehydrate through the usual graded alcohols. 



13. Clear in xylol. 



14. Mount in D.P.X., Clearmount, or other synthetic neutral 

 mountant. 



Results: 



The following are among the substances that are stained red 

 and are, therefore, described as being strongly " PAS-positive ": 



Gastric mucin Liver 



a- Glyceryl phosphate Serine 



Chitin Umbilical cord polysaccharide 



Glycogen Pneumococcus type 1 1 1 polysaccharide 



Hyaluronic acid 



The following are among the substances that take up the stain 

 with moderate intensity and are, therefore, described as being 

 moderately " PAS-positive " : 



Glucuronic acid Pneumococcus type i polysaccharide 



Starch Pneumococcus type 1 1 polysaccharide 



352 



