24 Tannin in the Fruit of the Persimmon [Sept 



is to be had by following the entrance of ammoniacal potassium 

 ferricyanid Solution into an intact cell. Previously (Lloyd, 1911), 

 I had thought the more rapid local reaction of the tannin-mass to 

 iron salts in an unbroken cell, observed also by Howard, to be due 

 to the more rapid penetration of the reagent through the shallovv 

 pores of the wall. This is true at certain stages of ripening. The 

 cell wall, however, undergoes slow hydrolysis, and after this has 

 proceeded for some time, the reagent finds entrance at numerotis 

 points, independently of the pores. The staining then begins at 

 these points, and by diffusion extends radially away from them, 

 thus producing circular areas of color. As these enlarge and 

 become more numerous, they coalesce, and thus the whole surface 

 becomes colored. During the progress of this staining, one may 

 observe a circular area formed on the edge of a superficial lentic- 

 ular pit, proving that the reagent has reached the fluid in this 

 pit. This, however, remains free from precipitate, a result which 

 would be impossible if there was any free tannin there (flg. 9). 



Somewhat later, the extrusion of the tannin-mass is sufficient in 

 extent to produce only a sub-spherical bubble-like protuberance, 

 usually on the side of the tannin-cell. This condition is well shown 

 by a photograph in Howard's paper of 1906 (fig. 6). At this time 

 the State of the tannin-cell is particularly favorable for the Obser- 

 vation of certain points. The amount of swelling may be increased 

 very considerably by using ammoniacal potassium ferricyanid Solu- 

 tion (fig. 7) while the transparent reactions facilitate Observation. 

 In such cells the disruption and expulsion of the protoplasm, nu- 

 cleus, and the internal cavities and canals may be followed. It is 

 important to point out that the expelled protoplasm must not be 

 confused with the granulär precipitate of free tannin, either within 

 the cell or without. I have been able to show clearly that the proto- 

 plasm remains, except under special circumstances, entirely free 

 from tannin during ripening (fig. 10). I must also draw atten- 

 tion to the preservation of the cavities and canals, which may 

 be found in the extruding portion of the tannin-mass (fig. 29), and 

 frequently opening on the surface (fig. 11). 



Upon the addition of ammoniacal potassium ferricyanid Solu- 

 tion, the superficial layer of the tannin-mass may rupture, exposing 



