LABORATORY DIRECTIONS. 477 



Heidenhain's Iron Hematoxylin. 



Sections that have been fixed in sublimate solu- 

 tions are placed in a 2.5 per cent, aqueous 

 solution of ammonium sulphate of iron for four to 

 eight hours. Rinse thoroughly in water and place 

 in a hematoxylin solution prepared as follows : 



Hematoxylin crystals 1 gm. 



Absolute alcohol 10 c.c. 



Distilled water 90 c.c. 



Dissolve the hematoxylin in the alcohol and add the 

 water. This solution should stand in an open vessel 

 for four weeks, and before using should be diluted 

 with an equal volume of distilled water. 



Stain, the above sections twelve to twenty-four 

 hours, rinse in tap water and return to ammonium 

 sulphate of iron solution until black clouds cease to 

 be given off from the sections. Rinse in distilled 

 water, dehydrate, and mount in balsam. 



This is a good stain for mitosis. 



Anilin Stains. 



These are basic or acid stains. The basic stains 

 are safranin, methylene-blue, methyl green, gentian 

 violet, methyl violet, Bismarck brown, thionin, and 

 tolUidin blue, and stain nuclei. The acid stains are 

 eosin, erythrosin, acid fuchsin, orange G. and nigro- 

 sin, and stain cytoplasm. 



These stains are used in water solutions and of 

 \ to i per cent, strength, to which a little alcohol 

 may be added. 



Pal-Weigert Method of Staining Sections of Brain 

 or Cord. 



Mordant celloidin sections for twenty-four hours 



