191 1] Francis Ernest Lloyd 39 



a small amount of tannin which does not unite with the colloids 

 present. 



The view is advanced that, during ripening, the supposed cellu- 

 lose-mucilage increases in quantity and that sufficient is at last 

 formed to engage most of the tannin. When mature, the tannin- 

 mass contains nearly, but usually not entirely, all of the free tannin 

 in a condition^^ which prevents its extraction by ordinary sol- 

 vents and its detection by alkaloids as reagents. In order to separate 

 all the tannin from the tannin-colloid Compound, drastic chemical 

 methods must be used. Decomposition of the tannin by means of 

 strong mineral acids, carried on more rapidly than the hydrolysis 

 of the associated colloid, has been used to effect this change. Some 

 evidence has been advancd to indicate the nature of this associated 

 colloid. It is probably a cellulose-mucilage. 



V. BIBLIOGRAPHY 



1906. Bigelow, W. D., Gore, H. C, and Howard, B. J. Growth and ripening 



in persimmons. Jour. Am. Chem. Soc., 38 : 688-703. June, 1906. 

 i9o3. Gross, G. F., Bevan, E. J,, and Beadle, G. Cellulose, etc. 2nd ed. 



London, New York and Bombay. 

 1910. Le Duc, St. Theorie physico-chemique de la vie et generations spon- 



tanees. Paris. 

 1910. Gore, H. G. (Ripening of persimmons.) Minutes of paper presented 



bef ore the Botanical Society of Washington, Science, n. s., 32 : 807. 



Dec. 2. 

 1906. Howard, B. J. Tannin cells in persimmons. Bull. Torr. Bot. Club, 



33: 567. Nov. 

 1888. af Klercker, J. E. F. Studien über die Gerbstoffvacuolen. Bihang tili 



K. Svenska Vet.-Akad., 13: Afd. III., No. 8. L-62, (repaged?), taf. l. 



Stockholm. 



191 0. Lloyd, Francis Ernest. Development and nutrition of the embryo, 



seed and carpel in the date, Phoenix dactylifera. Ann. Rep. Mo. Bot. 

 Garden, 21 : 103-164, 4 pl. Dec. 22. 



191 1. Lloyd, Francis Ernest. (a) The behavior of tannin in persimmons, 



with some notes on ripening. Plant World, 14: 1-14. Jan. (&) Tan- 

 nin-colloid combinations in the persimmon. Johns Hopkins University 

 Circular. (In press.) 

 1886. Pfeffer, W. Über Aufnahme von Anilinfarben. Untersch. a. d. Bot 

 Inst. z. Tüb. Bd. 2. Hft. 2. Leipzig (through af Klercker, 1888). 



^Dr. J. Dekker suggests {in literis) that unless the tannin has been changed 

 chemically it may still be partly extracted by alcohol or water. Such a change, 

 indicated by slight reddening of the tannin mass, ensues slowly in the overripe 

 fruit. 



