SECTION TWO 



under the microscope and if the nuclei are not stained a bright and 

 transparent blue and the cytoplasm (except mucin and basophile 

 granules of mast cells, etc.) is not colourless, rinse in water and 

 repeat the staining and bluing process. 



If, on the other hand, overstaining has taken place, immerse the 

 preparation in 0-5% HCl for five to thirty seconds; then immedi- 

 ately rinse in water, " blue " in tap water and again examine under 

 the microscope; if the sections are still overstained repeat the 

 treatment with HCl; rinse and " blue " in tap water again. 



5. Wash well with water; then stain from two to five minutes 

 in eosin solution. 



6. Rinse quickly in water and examine the section rapidly, while 

 still wet, under the microscope to ensure that the depth of the 

 counterstain is sufficient. The cell cytoplasm, collagen, connec- 

 tive tissue fibres, erythrocytes, etc., should be stained a bright 

 transparent pink. It is advantageous to overstain somewhat with 

 the eosin, as subsequent dehydration in the alcohols will remove 

 the excess eosin. 



7. Dehydrate by passing rapidly through 70%, 90% and abso- 

 lute alcohol. 



8. Clear in xylol ; mount in balsam. 



Results: 



Nuclei are stained dark blue; karosomes, dark blue; plasma- 

 somes, red ; cytoplasm (except when basophile) is stained in varying 

 shades of pink; muscle and collagen fibres, pink; elastic fibres 

 (when thick), pink; erythrocytes, thyroid colloid and keratin, 

 bright pink. 



HAEMATOXYLIN - FLUORCHROME (Kultschitzky-Pal) 



For myelin sheaths. Particularly suitable for demonstrat- 

 ing very fine fibres in cerebal cortex, etc. 



Solutions required: 



A. Weigerfs rapid fixative : 



Fluorchrome . . . . . . 2 gm. 



Potassium bichromate . . • • 5 gni- 



Distilled water . . . . . . 100 ml. 



Add the potassium bichromate to the water ; boil ; 

 add the fluorchrome; cool; then filter. 



115 



