8 Tannin in the Fruit of the Persiinmon [Sept. 



contrary to the previously held view that it disappears^ during ripen- 

 ing, by oxidation (Gerber, Aso, Sawamura), or is changed in one 

 way or another.^ That this insokible tannin presents certain phys- 

 ical pecidiarities not to be expected in tannin itself has been noticed 

 in the date by Vinson (1910), who speaks of the tannin-masses as 

 f racturing " like grains of gelatin," and in the persimmon by 

 Howard (1906), who describes at length the pecuharities of the 

 physical behavior of the tannin-mass during the course of ripening. 

 His observations have, in large measure, been verified by me, and I 

 have so reported in the Plant World, as above cited. I found 

 myself, however, in disagreement with this author on the score 

 of the structure of the tannin-idioplast as a whole, and as to the 

 origin of certain material, spoken of by him as "whitish particles" 

 which " on further examination are found to be the expelled cell- 

 contents, which on coming in contact with abundance of water . . . 

 assume a white granulär appearance" (Howard, 1906, p. 573). 

 Concerning this material I have ventured the assertion that its gran- 

 ulär appearance is not due to the assumption of this by the "cell- 

 contents," and in differing with Howard, I should say clearly that 

 I took his expression "expelled cell-contents " to mean the ex- 

 truding tannin-mass. I think this is the normal and proper Inter- 

 pretation of the words in the connection in which they occur, but 

 I mention the basis of my Interpretation in order to avoid possible 

 injustice. As to the presence, under certain conditions, of the 

 " whitish particles " which have a finely granulär appearance there 

 can be no question, but at the time when my previous paper was 

 written, I was unable to give a satisfactory account of their origin. 

 But although the curious appearance and behavior of the tannin- 

 masses have been noted, there has been no attempt at their explana- 

 tion although they are quite out of harmony with accepted criteria 

 of tannin as such. Certainly, from the microchemical point of 

 view, these are most interesting facts, and to the plant physiologist 

 of very special moment. Using chemical methods, it has already 

 been shown by Bigelow, Gore and Howard (1906) that, during 



'Thompson and Bassett (1911) have advanced a stimulating view to the 

 effect that tannin does not exist as such in the normal growing fruit (pear), 

 but is rapidly formed, by an enzyme, on injury or removal from the tree. 



* The various explanations which have been advanced, were reviewed by 

 Dekker (1906) and by Bigelow, Gore and Howard (1906, p. 692). 



