Tannin in Persimmons. 5 



The plasmatic membrane, which contains carotin bodies, is thin 

 except in restricted areas, and the nucleus is lateral in position . 

 The vacuole is occupied, in the ripe fruit, by a tannin-mass (or 

 two or more) suspended in the sap. The protoplasm docs not 

 lie immediately against it at all points (figs. 2, 8). The origin 

 and behavior of this tannin mass calls for special discussion. 



The tannin-mass. I use this somewhat clumsy term to 

 avoid, in a degree, the idea that the tannin content of the cells 

 in question is a watery solution, or that it is merely tannin. I 

 hold that neither of these conceptions is correct, but I do not 

 venture to assert that the proof of them is complete. 



The working theory which is here adopted is that the tannin 

 is associated with a mucilaginous or gelatinous substance which 

 acts as a carrier, and that its insolubility in the ripe fruit is due 

 to its chemical imion with this carrier, in the fashion that tannin 

 unites with gelatine, glue, et cetera, in vitro. This explanation 

 may not be new, but I do not find that any studies have been 

 made to throw light especially on this point * Howard, it is 

 true, has given us some information, and has used expressions 

 which show that the presence of a mucilage or mucilage-like 

 material may have been suspected by him. The possibility, 

 however, that the tannin is united with some "undetermined 

 solid" is set aside for the view that the "tannin itself becomes 

 insoluble within certain specialized cells." It will be seen that 

 my view, as above stated, is at variance wnth that of Bigelow, 

 Gore, and Howard, as stated in their joint paper of 1906. In 

 taking this issue, I do not claim full conviction, except as to the 

 point that the tannin as such becomes insoluble. The explana- 

 tion itself requires to be explained, since such a change, unac- 

 companied by any other, chemical or physico-chemical, appears 

 to be highly improbable. At the start, how^ever, we must note 

 that inquiry into the matter is balked by the difficulty of apply- 

 ing suitable tests to the tannin masses. Tannin tests give the 

 same color results whether the tannin is free or combined with a 

 colloid. I have examined for comparison with the tannin 

 masses, tannin-gelatine, tannin-agar, and tannin-albumen. The 

 result obtained is that these substances, particularly the tannin- 

 gelatine and albumen, behave in almost all respects like the tan- 

 nin-masses in the ripe persimmon. There is a slight quantatitive 



*Becau5e I have not yet seen f Klerker's paper in the original form, I fear that I may do 

 him scant justice 



