124 Microscopic Histochemistry 



sue should be fixed in Regaud's mixture ( 10 per cent formalin 

 containing 5 per cent potassium dichromate ) . Mercury-con- 

 taining fixatives, such as Zenker's fluid, give much poorer 

 results. In the finished sections adrenalin-containing cells 

 appear in a more or less dark-brown shade. 



The argentafiin reaction (Ogata," Baginski'^) is not rec- 

 ommended; it does not give a sharp localization. 



The ENTEROCtmoMAFFiN (EC) Substance 



The granules of the EC cells show a number of interesting 

 staining reactions, some of which are capable of a chemical 

 interpretation. All the reactions to be mentioned here can be 

 ehcited even after prolonged formalin fixation. 



1. The granules are chromaflfin.^*^ 



2. They are argentafiin,^^ even after fixation in dichromate- 

 containing mixtures. 



3. At an alkaline reaction tliey give intensely colored azo 

 dyes with diazonium compounds.^^* ^^ 



4. They give a fairly intense indophenol reaction,^* espe- 

 cially with Gibbs's reagent. 



5. They reduce ferriferricyanide to Prussian blue. 



In addition to these reactions, they stain intensely with 

 some lake dyes (hematoxylin, gallocyanin, celestin blue, etc. ) 

 in the absence of metal salts.^^ The chemical explanation of 

 this staining property is not clear. They are also stained by 

 various silver-impregnation techniques, such as Bodian's"^ 

 (this is not an argentafiin reaction; see p. 58 ) . 



On the basis of their chemical reactions, which are the 

 same as those of adrenalin in the test tube (Verne^^), Cor- 



19. Baginski, S.: Bull, d'histol. appliq. a la physioL, 5:129, 1928. 



20. Heidenhain, R.: Arch. f. mikr. Anat., 6:368, 1870. 



21. Masson, P.: Compt. rend. Acad, sc, 158:59, 1914. 



22. Cordier, R., and Lison, L.: Bull, d'histol. appHq. a la physiol., 7:140, 



1930. 



23. Lison, L.: Arch, de biol., 41:343, 1931. 



24. Jonnard, R.: J. de phys. et de path, gen., 32:731, 1107, 1934. 



25. Clara, M.: Ztschr. f. Zellforsch. u. mikr. Anat., 22:318, 1934-35. 



26. Dawson, A. B.: Anat. Rec, 91:53, 1945. 



