' 87 



previously prepared, (a). Carmine, 1 gram; ammonium chlorid, 

 2 grams; lithium carbonate, 0.5 grams; distilled water, 50 c. c. 

 Bring the mixture to a boil. When it is cool, add 20 c. c. 10% am- 

 monia. Preserve the solution in the dark; after 2 to 3 days it is 

 ready for use and retains its staining quality for a few weeks only, 

 (b) When ready to stain, filter the above solution (a), and add to 

 2 parts of the stain, 3 parts of 10% ammonia solution, and 6 parts 

 of methyl alcohol. 



Stain sections 1 hour, differentiate in a mixture of 2 parts of 

 methyl alcohol, 4, parts of absolute alcohol, 5 parts of water; rinse 

 with 82% alcohol, dehydrate, clear and mount in balsam. Glycogen 

 stained an intense red. 



In working with glycogen it is sometimes necessary to apply as 

 a control the digestion of the glycogen in one or more sections or a 

 part thereof, by means of saliva. 



C. Amyloid. 



Amyloid, a form of connective tissue degeneration, resembles 

 glycogen in some of its physical (not chemical) properties and stain- 

 ing reactions. Two methods for its demonstration may be men- 

 tioned : 



231. Iodine Method. Practically any fixer may be used 

 (Zenker's fluid). Paraffin, celloidin, or (better) frozen sections 

 may be used. Stain sections with the iodine solution ( 229) for 

 several minutes; rinse in distilled water and transfer to glycerin or 

 glycerin-jelly ( 151, 155) in which they may be mounted. Seal the 

 preparations ( 162 ). The amyloid a reddish-brown; the stain, 

 however, will fade in the course of a few months. 



232. Gentian Violet, among other anilin stains, colors amyloid 

 differentially (metachromasia). Stain paraffin sections for several 

 minutes in a 1% solution of the stain; rinse and differentiate in 1% 

 acetic acid; wash thoroughly with distilled water, and (a) mount in 

 glycerin- jelly, or (b) dry in the air, treat with xylene and mount in 

 balsam. In the latter procedure, the staining may be applied before 

 removing the paraffin. 



D. Mucus. 



Mucous substances (mucins, mucinoids) possess acid properties 

 combining with alkalis and bases (heavy metals), such combinations 

 swelling up or dissolving in water. Acetic acid, alcohol and picric 

 acid also precipitate these substances. For the fixation of mucus, 



