Mast Cells 281 



2. Stain in thionin: 5-15 minutes. 



3. Rinse in distilled water. 



4. Treat with molybdate-ferricyanide: 2 minutes. 



5. Wash in distilled water: 2-3 minutes. 



6. Dehydrate, clear, and mount. 



results: 



acid mucopolysaccharides — purple 

 other cell elements — bhiish 



comments: 



The molybdate-ferricyanide soliuion prevents loss of metachromasia. 

 See Kiiyer {19^1) for suggestions concerning fluorescent methods 

 for mucopolysaccharides. 



Mast Cells'" 



Thionin Method (levine, 1928) 

 fixation: any general fixative. 



solutions: 

 Thionin: 



thionin, C.I. 52000 1.0-2.0 gm. 



distilled water 100.0 ml. 



Orange G: 



orange G, C.I. 16230, saturated solution in oil of cloves. It goes into 

 solution slowly; stir frequently. Allow to stand 24 hours before using. 

 Good until it becomes discolored by thionin. 



procedure: 



1. Deparaffinize and hydrate slides to water; remove HgClo. 



2. Stain in thionin: 2-3 minutes for light stain; 10-15 minutes for 

 an intense stain. 



3. Rinse briefly in water for light stain; blot around sections for in- 

 tense stain. 



4. Dehydrate by dropping a few drops of absolute alcohol on sections. 



5. Stain with orange G-clove oil: 1-2 minutes. Repeat orange G until 

 thionin disappears from cytoplasm, leaving it orange. Mast cells 

 remain unchanoed. 



6. Clear thoroughly in xylene, and mount. 



"Sec Mast Cell Slaining, page 276. 



