GENERAL TECHNIC 21 



After being thoroughly washed in water, they are dehydrated in 

 strong alcohol and transferred to the alcoholic eosin solution (page 

 20). Most sections stain in from two to five minutes. By this 

 method nuclei arc stained blue or ])urj)Ie, cell bodies and intercellular 

 substances red. 



Very often a more brilliant staining may be accomplished as 

 follows: Overstain in haematoxylin and wash thoroughly in water; 

 decolorize in water slightly acidulated (8 or 10 drops of hydrochloric 

 acid to 100 c.c. of water) until only the nuclei retain the stain; wash 

 in water which has been made slightly alkaline with ammonium hy- 

 drate; then stain with eosin as usual. 



(2) Staining with Picric-acid-fuchsin (Van Gieson). 



Acid-fuchsin, i-per-cent. aqueous solution, 5 c.c. 



Picric acid, saturated aqueous solution, 100 c.c. 



This solution usually stains in from one to three minutes. Occa- 

 sionally a longer staining is required. Cell bodies including muscle 

 cells and fibres are stained yellow by the picric acid, connective- 

 tissue fibres red by the fuchsin. After staining, the sections are 

 washed in distilled water. 



(3) Triple Staining with Hematoxylin and Picro-acid- 

 FUCHSiN. — This is the same as the preceding except that before stain- 

 ing with picro-acid-fuchsin, the sections are overstained in haema- 

 toxyHn (solutions i, 2, 4, 5, or 6, pp. 17-19). The usual purple of \ 

 haematoxylin-stained nuclei is changed to brown by the action of the 

 picric acid. Care should be taken that the sections do not remain 

 too long in the picro-acid-fuchsin, or the haematoxyhn may be com- 

 pletely removed. After staining, sections are washed in distilled 

 water and transferred to 96-per-cent. alcohol. 



If sections overstain with fuchsin, the staining solution may be 

 diluted with water; if sections are understained with fuchsin, more 

 fuchsin may be added. If the picric-acid stain is not sufficiently 

 intense, the 96-per-cent. alcohol should be tinged with picric acid. 



(4) Staining with Picro-carmine. 



Ammonium carminate, i gm. 



Distilled water, 35 c.c. 



Picric acid, saturated aqueous solution, 15 c.c. 



The ammonium carminate is first dissolved in the water, after which 

 the saturated aqueous solution of picric acid is added with constant 

 stirring. The mixture is then allowed to stand in an open vessel for 



\ 



-=«*. 

 "■'N.^ 



