156 Microscopic Histochemistry 



ions in favor of the catalytic but nonenzymatic nature of the 

 reaction. 



It is known that the formation of indophenol blue from the 

 nadi reagent can be catalyzed nonenzymatically. The posi- 

 tive reaction given by unsaturated fats has been mentioned 

 before (p. 110). Remesow^^ obtained positive reactions with 

 irradiated cholesterol. In model experiments filter-paper 

 strips moistened with a solution of linseed oil or oleic acid 

 in chloroform were allowed to dry for 12-24 hours. An in- 

 tense blue color was observed after 1 minute's immersion in 

 the nadi reagent. Schiimmelfeder^^ reported negative results 

 with oleic acid in similar experiments. It must be assumed 

 that he did not allow enough time for the formation of per- 

 oxides. The presence of peroxides in oleic acid was proved 

 by Lison.*^ He shook a solution of benzidine and hemoglobin 

 with oleic acid (in place of H2O2 as the peroxide) and ob- 

 tained the typical shade of benzidine blue in the aqueous 

 phase, just as if hydrogen peroxide had been employed. 

 Nadi-positive lipid substances have been prepared by sev- 

 eral workers. ^^ The lipid nature of the granules of the mye- 

 loid elements has been demonstrated repeatedly, and the 

 morphological appearance of the Sudan-stained substance is 

 identical with that of the nadi-positive granules. ^^ Sehrt^* 

 could prove that sudanophilia and staining by the nadi reac- 

 tion invariably run parallel; if a lipid solvent abolishes one, 

 it will abolish the other. 



On the basis of these facts, it would seem that the enzy- 

 matic theory is a superfluous assumption; the formation of 



39. Remesow, I.: Virchows Arch. f. path. Anat., 285:591, 1932. 



40. Schiimmelfeder, N.: Virchows Arch, f, path. Anat., 317:707, 1950. 



41. Lison, L.: Bull. Soc. chim. biol., 18:185, 1936. 



42. Neumann, A.: Arch. f. exper. Zellforsch., 6:298, 1928; Gutstein, M.r 

 Biochem. Ztschr., 207:177, 1929; Magat, J.: Compt. rend. Soc. de biol., 

 116:1367, 1934. 



43. Dietrich, A.: Ergebn. d. allg. Path. u. path. Anat., 13:283, 1909; 

 Marinesco, G.: Compt. rend. Soc. de biol., 82:258, 1919. 



44. Sehrt, E.: Miinchen. med. Wchnschr., 74:139, 1927. 



