20 Tannin in the Fruit of tlie Persimmon [Sept 



yellow, the tannin-cells will still be found to burst when placed in 

 water. The tannin-mass canses this by its swelling, but the capac- 

 ity for imbibition is now not so great as before. It results that, 

 as Howard has described, the tannin-mass breaks out at some 

 point, usually laterally, sometimes at the end of the cell. This burst- 

 ing may now be seen to be due solely to the imbibing of water by 

 the tannin-mass (Lloyd, 1191), and not to the behavior of the re- 

 maining cell contents to water. This is clearly shown by the interac- 

 tion of the tannin-mass and the vacuoles, resulting in the displace- 

 ment and final bursting of these within the protoplasm or at any rate 

 weithin the cell wall (fig. 22, a and h). The protoplasm is dis- 

 rupted, and the nucleus displaced and compressed. The cell-wall 

 is finally stretched and then broken open, a rounded hole being 

 formed by pushing off a piece of wall of relatively large dimen- 

 sions. Out of this hole a rounded extrusion projects from the 

 tannin-mass, its size depending on its imbibition capacity (figs. 

 12-14). This during ripening becomes progressively less until 

 it is not great enough to effect the bursting of the cell, though the 

 wall may be stretched nearly to its limit of strength. Under some 

 conditions within the fruit, not well defined in my own mind as 

 yet, the tannin-mass may stay pemianently in this condition, unless 

 dried out by evaporation, or it may pass into a State in which the 

 total imbibition capacity is very small, even w^hen completely dry. 

 When in this condition, the tannin-mass appears slightly angular, 

 pitted with a few depressions, transversely or spirally corrugated 

 and frequently lobate. One or all of these appearances may be ab- 

 sent, but at any rate the mass appears to be, as it is, shrunken. In the 

 interior, the canals and cavities, already described, may some- 

 times remain, or more usually, they may be entirely absent. The 

 number of superficial pits or lenticular cavities may be greater 

 than before. This condition, thought by Howard to be constant, 

 may result, I think, from the displacement of the internal cavities 

 to the surface of the tannin-mass. An intermediate condition, in 

 which the internal cavities are present, but from which the canals 

 are absent, indicates this. But such a condition may arise only 

 by internal compression exerted in all directions, and this, in turn 

 only by the swelling of the tannin-mass sufficiently to exert pres- 



