636 APPENDIX. 



For use, mix equal parts of A and B. The mixture will keep 2 or 3 days. See "Staining 

 with hematoxylin and eosin." 



Heidenhain's hematoxylin. — Make up stock solutions as follows: 



A. Hasmatoxylin, 1 per cent, solution in distilled water. 



B. Ammonium sulphate of iron, 2.5 per cent, aqueous solution. 

 For using, see "Staining with Heidenhain's hematoxylin." 



Eosin. — Dissolve water-soluble eosin to saturation in water. Precipitate with hydro- 

 chloric acid and wash with water until the filtrate is tinged with eosin. Dry the precipitate 

 and dissolve in 95 per cent, alcohol in the proportion of 1 gram to 1500 c.c. of alcohol. 



Acid fuchsin (Fuchsin S, Rubin S). — This is generally used in a 0.5 per cent, solution in 

 distilled water. It is very sensitive to alkalies and to avoid washing out the stain, distilled 

 water should be used for washing the sections. The dye known as Orange G is used in the 

 same solution and with the same precautions (see also p. 290). 



Picric acid and acid fuchsin (Picro-acid fuchsin). — 



Acid fuchsin, 1 per cent, aqueous solution . 5 c.c. 



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



For using, see under "Staining with hematoxylin and eosin." The proportions may be 

 varied if desired. 



Staining celloidin sections with hcematoxylin and eosin. — Starting with sections in 80 per 

 cent, alcohol, transfer to — 



1. Water. 



2. Delafield's or Weigert's hematoxylin, several minutes. 



3. Water (to wash). 



4. Water acidulated with HC1 (6 drops of HC1 to 50 c.c. of water) until tissues appear 

 gray. 



5. Water made slightly alkaline with ammonia. 



6. Water, several changes. 



7. Alcohol, 80 per cent. 



8. Eosin solution until tissues are pink. 



9. Alcohol, 95 per cent. 



10. Carbol-xylol (carbolic acid, 1 vol.; xylol, 3 vols.). 



11. Pure xylol (one change). 



12. Mount in xylol-damar. 



If many sections are to be stained it is most convenient to carry them through the various 

 fluids up to 95 per cent, alcohol in small sieves or perforated porcelain dishes and then 

 transfer them one by one to the carbol-xylol. 



If acid fuchsin, instead of eosin, is to be used as a counter-stain, carry the sections through 

 the various fluids up to and including (6). Then immerse in the fuchsin solution until the 

 tissues are pink (several seconds to several minutes), wash in distilled water and continue the 

 steps as given, omitting of course the eosin solution. 



The picric acid and acid fuchsin mixture is used in exactly the same way as the fuchsin. 

 Staining paraffin sections with hematoxylin and eosin— It is most convenient to have the 

 fluids in Coplin jars. Starting with sections on slides from which the paraffin has not been 

 dissolved, transfer to — 



1. Xylol, two successive baths. 



2. Absolute alcohol, two successive baths. 



3. Alcohol, 95 per cent. 



4. Alcohol, 80 per cent. 



5. Water. 



