STAINING, PRACTICAL AND THEORETICAL 



Notes: 



(a) The staining is progressive and should be controlled under 

 the microscope as the density of colour and rapidity with which 

 it is taken up varies with the species of animal and the state of 

 the individual mast cells. 



(b) The addition of nitric acid to the tribasic stain (solution H) 

 reduces the affinity of the latter for nuclei and at the same time 

 increases its selectivity for mast-cell granules, although other 

 mucopolysaccharide-containing tissue elements also take up the 

 stain to some degree. Of these, cartilage reacts most strongly, 

 while gastric mucin, keratin, and elastic tissue may stain weakly, 

 usually in a slightly different shade of red. 



Reference: Barlow, R. M. (i957)- 



TRICHROME STAIN (Gomori) 



Solutions required: 



A. Delafield or Ehrlich Haematoxylin. 



B. Lithium carbonate i% aqueous. 



C. Alcohol 70% 97 ml. 



HCl, concentrated . . . . • • 3 ^^ 



D. Picric acid 1% in 50% alcohol. 



E. Phosphotungstic Acid 3%, 



F. Light green, or Fast green FCF, or 



Aniline blue 0-5 gm. 



Neoponceau (Michrome) . . . . 1-5 gm. 



G. Solution F i volume 



Acetic acid 2% . . . . 3 to 4 volumes 



Technique: 



1. Fix tissues in Bouin or 10% Formalin. 



2. Stain sections in the Haematoxylin solution for ten minutes. 



3. Blue in the lithium carbonate solution. 



4. Differentiate, if necessary, with the HCl alcohol for pre- 

 dominance of the green or blue shades, or in picric alcohol for 

 predominance of red shades, in the final picture. 



450 



