i6 Tannin in the Fruit of the Persimmon [Sept. 



where a sap vacuole occupies the space. The cavity is therefore 

 lined by protoplasm, this surrounding the vacuole (Lloyd, 191 1, 

 figs. 2, 8.) In every case, therefore, the canals which open on the 

 surface of the tannin-mass, even thoiigh they do so 011 the hollow 

 surface of a superficial cavity, open into the thin Space, occupied 

 by a film of water, lying between the protoplasm and the surface 

 of the tannin-mass. 



The canals are therefore such only secondarily, and mark 

 the limits of former surfaces. They may have the width of a 

 micron, seldom more, and frequently less, while the cavities may 

 be several microns in diameter. One can see in them either noth- 

 ing at all, which means of course that they contain water with 

 no visible suspensions; or minute granulär bodies, often large 

 enough to be recognized as spherical, may be observed. I have 

 found no method of differential staining to separate these Contents 

 visually from the tannin-mass, since whatever stains the latter 

 obscures or occludes the former. The most natural expectation is 

 that they contain tannin in Solution in the water which fills them. This 

 can be neither proved nor disproved by any means that I have used 

 but that, under some conditions, they do contain a watery Solution 

 of tannin follows from certain observations to be cited beyond. 

 There is some evidence also that the spherical granules consist of 

 the same substances as those of the tannin-mass itself, inasmuch as 

 similar masses giving a tannin reaction are sometimes found in a 

 Position rendering their reactions visible (fig. 34). 



III. PHYSICAL AND CHEMICAL PECULIARITIES OF THE TANNIN- 

 MASS DURING THE COURSE OF RIPENING 



General considerations. While the fruit is still hard, the 

 tannin-mass is so soft that it flows easily. After the process of 

 softening has been fully initiated, the tannin-cells may be isolated 

 successfully, without in the least injuring them, while the tannin- 

 mass is still mobile enough to flow, like a weak Solution of mucilage. 

 If one selects a suitable cell having readily visible cavities, places a 

 supported cover-glass over it, and, while under Observation under 

 fairly high magnification, runs water under the cover, the tannin- 

 mass will quickly absorb enough water to cause the cells to burst 



