1913] Ernest D. Clark 417 



he was unable to say whether it occurs as a waste product or one 

 useful in the synthetic processes. 



Waage^ made some interesting observations in regard to phloro- 

 glucinol in plants. He confirmed the Statement that the substance is 

 widely distributed in plants and suggested that it might arise during 

 photosynthetic processes, just as glucose probably does. He feit 

 that, because of the dark blue color given by phloroglucinol and 

 ferric chlorid, and because of the bleaching of methylene blue by 

 the former substance, one cannot rely on the previous deductions in 

 regard to the presence of tannin in cell vacuoles based on these 

 reactions for tannin. In fact, he criticized, on the same ground, the 

 work of af Klercker^ on tannin in vacuoles. Schiff^*^ found that 

 under suitable conditions, phloroglucinol and carbon dioxid combine 

 to form phloro-tannic acid which, upon heating, yields a red sub- 

 stance like phlobaphene. Evidently, tannin is present along with 

 phloroglucinol in many plants, but the physiological röle of these 

 substances is as little known as is the nature of the combination 

 between them in cases like that of the tannin masses of the per- 

 simmon, Much more work on persimmons will be necessary to 

 explain the part played by phloroglucinol in the loss of astringency 

 in the mature fruit. 



Summary. Tannin masses from the fruit of the persimmon, 

 by hydrolysis with weak acid or alkali, yield tannin, phloroglucinol, 

 and considerable insoluble colloidal residue. Hydrolysis of such 

 tannin masses does not produce hexose or pentose. 



The nature of the union between the tannin and phloroglucinol 

 is unknown but it is probably similar to that of the phloroglucin- 

 tannoids in various plants. 



The colloidal residue that resists hydrolysis seems to be a cellu- 

 lose-like substance, which readily forms gelatinous masses with 

 water or alkaline Solutions. Quantitative studies on large amounts 

 of this third substance are desirable. 



In the presence of phloroglucinol, the ferric chlorid test for 

 tannin is unreliable. 



* Waage: Ber. d. d. bot. Ges., 1890, viii, p. 250. 



'af Klercker: Bihang tili K. Svenska Vet.-Akad., 1888, xiii, p. 18 (repaged?). 



*• Schiff : Ann. d. Chem., 1888, ccxlv, p. 36; 1889, cclii, p. 87. 



