41 6 "Tannin Masses" in Fruit of the Persimmon [April 



are similar to those obtained with acids, except that alkali accelerates 

 oxidation by atmospheric oxygen. 



Properties of mixed Solutions of pure tannin and phloro- 

 glucinol. Mixtures in varying proportions of Solutions of pure 

 tannic acid and phloroglucinol were tested and found to show many 

 similarities to the hydrolytic products of the tannin masses. The 

 Molisch test was strongly positive. With ferric chlorid such mixed 

 Solutions gave a purplish black color which was accompanied by the 

 gradual formation of a precipitate of the same shade. The typical 

 influence on Fehling-Benedict Solution was observed ; namely, heavy 

 greenish precipitation at first but, upon heating, this changed to a 

 characteristic red reduction. When some of the mixed Solution was 

 evaporated with the vanillin-hydrochloric acid reagent, a definitely 

 positive result was obtained but the tannin seemed to cause a 

 brownish tint not given by phloroglucinol alone. 



Pure phloroglucinol Solutions were negative to the Molisch test 

 and also to the Fehling-Benedict test. Ferric chlorid Solution pro- 

 duced a clear blue color with pure phloroglucinol but did not give 

 a precipitate, thus differing f rom tannin, which forms a blackish pre- 

 cipitate at once under these conditions. Solutions of pure tannin 

 yield a typical Molisch test and reduce Fehling-Benedict Solution in 

 the characteristic manner just described. It is evident that, in the 

 presence of phloroglucinol, one cannot conclude that a purple color 

 with ferric chlorid indicates tannin. The addition of nitric acid to 

 the mixture already turned purple by ferric chlorid caused an in- 

 stantaneous change to a brownish tint. 



It is obvious, then, that, in the tests indicated, mixtures of tannin 

 and phloroglucinol differ in no essential way from the hydrolytic 

 products of the tannin masses. 



Sources of the tannin and phloroglucinol in the tannin 

 masses. The material in the tannin masses from which tannin and 

 phloroglucinol are derived by hydrolysis is probably one of the so- 

 called phloroglucin-tannoids, which were found by Graebe® to yield 

 these hydrolytic products by treatment with acids, etc. WeinzierF 

 showed that phloroglucinol is widely distributed among plants but 



* Graebe : Ber. d. d. ehem. Ges., 1903, xxxvi, p. 212. 



'Weinzierl: Oesterr. bot. Zisch., 1874, xxvi, p. 285. See also Nickel: Bot. 

 Centralblatt., 1891, xlv, p. 394. 



