STAINING REAGENTS. 



6 7 



and cover. Such sections improve with keeping, and the surplus 

 picro-carmine is really an advantage, for, after a time, the nuclei 

 become more differentiated red, and other parts yellow. 



If it be desired to mount sections stained with picro-carmine in 

 balsam, the alcohol through which they are passed, or the clove-oil, 

 must contain some picric acid to restore the yellow colour. 



11. Carmine and Dahlia Fluid ( Westphal}. Dissolve i gram of 

 carmine in 2.5 per cent, of alum. Take of this 



Alum carmine . 



Glycerine 



Sat. sol. of dahlia in absolute alcohol 



Acetic acid 



100 cc. 



100 



100 



20 ,, 



This fluid is specially useful 

 (" Mastzellen ") of the liver. 

 12. Cochineal (Csokor). 



Powdered cochineal 

 Alum . 

 Water . 



for staining the granular cells 



50 grama. 



5 

 500 cc. 



Dissolve the alum in the water, add the cochineal (Coccus cacti), 

 and boil. Evaporate down to two-thirds of its original volume. 

 Filter. Add a few drops of carbolic acid to prevent the formation 

 of fungi. This is an excellent nuclear stain, especially for the 

 central nervous system. 



It stains nuclei of a violet-red and does not overstain, so that 

 sections may be left in it for many hours. It, however, does not 

 stain well objects that naturally stain with difficulty. 

 Application. 



(1.) Stain for an hour or more. 

 (2.) Wash in water. 

 (3.) Alcohol, oil, balsam. 



13. Indigo Carmine (MerJceT). 



Solution A. Carmine . 

 Borax 

 Water . 



Solution B. Indigo carmine 

 Borax 

 Water 



2 grams. 

 8 

 1 30 cc. 



8 grams. 

 8 

 130 cc. 



Keep the solutions separate (B is apt to develop a precipitate). 

 When required, mix equal volumes of A and B. The mixture 

 undergoes a change within a week, and hence it is better to make 

 it fresh when required. Sections must remain in it at least twenty- 

 four hours with advantage longer but the results are certainly 

 satisfactory. The stained sections are placed for half-an-hour or 



