28 NTJCLEAK STAINS. 



CARMINE. 



The principal uses to which. Carmine is applied are 

 (1) Staining in "bulk. (2) Staining sections of the nervous 

 system. For the former, Grenacher's Alcoholic Borax Carmine 

 is generally used, and for the latter Ammonia or Lithium 

 Carmine, Grenacher's Alum Carmine, or Czoker's Alum 

 Cochineal. (3) Staining Vegetable sections. 



For sections other than the nervous system Lithium Car- 

 mine or Borax Carmine are useful stains. 



Carmine under ordinary circumstances acts as a general 

 stain, affecting the ground tissue as well as the nuclei. By 

 subsequent treatment with Acidulated Alcohol or Acidulated 

 Glycerine the colour is discharged from the ground tissue 

 without seriously affecting the nuclei. Used in this way, 

 Carmine becomes a good nuclear stain. It is also used exten- 

 sively by some histologists in the form of Picro-carmine 

 Solution. 



Sections stained with the Carmines (except Alum Carmine) 

 should not be washed in Water as the colour will be to a great 

 extent removed, nor in Acidulated Water as the Carmine is pre- 

 cipitated on the sections. Acidulated Alcohol containing ^ or 

 1 p. c. of Hydrochloric Acid (sp. gr. 1/16), in 70 p. c. Alcohol, 

 or Acidulated Glycerine containing 1 p.c. of Glacial Acetic 

 or of Formic Acid (sp. gr. 1*2), in equal parts of Glycerine and 

 Water, should be employed. The former if Balsam be used 

 for mounting, the latter if Farrant or Glycerine be employed. 



STAINING IN BULK. 



This method is used only in preparing material for serial 

 cutting. 



Tissues are placed in Grenacher's Alcoholic Borax Carmine 

 from one to three days. They are transferred from the stain 



