14 The PtANT World, 



carrier, (a second colloid), with which it unites. The behavior 

 of tannin, if this explanation be found ultimately correct, is 

 therefore analogous to that of other substances which are 

 rendered insoluble by combination, e.^., oxalic acid with calcium. 



The final stages of ripening are probably independent of living 

 protoplasm at the time during which final softening takes place, 

 and are therefore due to it indirectly. This conclusion is also 

 supported by experiments,not here reported upon specifically, in 

 which chemical agents have been used to induce ripening earlier 

 or more rapidly than is normal. 



There is no intercellular tannin in a normal tissue. "When 

 such occurs it is due to accident e. (7. bruising causing the bursting 

 of the tannin-cells in situ. 



The capacity for imbibition on the part of the tannin-mass 

 sufficient to burst the cell-wall is not associated with astringency 

 to the taste during the whole of the period of ripening when such 

 bursting is possible. 



Although aside from the purpose of this paper, evidence is 

 obtained that the cell-walls of the pulp are digested. It has been 

 shown that they are not true cellulose, but pectocellulose. 



It is probable, in the light of earlier studies of the date, that 

 the above conclusions are applicable to this fruit also. 



Alabama Polytechnic Institute. 



Auburn, Alabama, 



PAPERS CITED. 



(FOR FURTHER LITERATURE SEE THE PAPERS BELOW.) 



1906. Bigelow, Gore and Howard. Growth and Ripening of Persim- 

 mons. Jour. Am. Chem. Soc., 38: 688. June. 



1905. Fairchild, D. The Japanese Method of Ripening Persimmons, 



Proc. Soc. Hort. Sci., p. 37. 



1906. Howard, B. J. Tannin Cells of Persimmons. Bull. Torr. Bot. 



Club, 33: 567. 

 1910. Lloyd, F. E. Development and Nutrition of the Embryo, Seed 

 and Carpel in the Date, Phoenix dactylifera, L. Ann. Rep. 

 Mo. Bot. Gard. Dec. 



1907. Vinson, A. E. Some Observations on the Date. Plant World, 



10: 259. Nov. 

 1910. Vinson, A. E. The Stimulation of Premature Ripening by 

 Chemical Means. Jour. Am. Chem, Soc, 32: 208. Feb, 



