40 Tannin in the Fruit of the Persimmon [Sept. 



1904. Tichomirow, Wlad. Sur les inclusions intracellulaires du parenchyme 

 charnu de certains fruits: Datte, Kaki, Jujube, Anone et Chalef. 

 Comptes Rendus, 139 : 305-306. Jy.-Dec. 



i9ii. Thompson, F., and Bassett, H. P. The preparation and properties of 

 an oxidase occurring in fruits. (Digest.) Science, n. s., 33: 343. Mar. 3. 



1910. van Wisselingh, C. On the tests for tannin in the living plant and on 

 the physiological significance of tannin. Proc. K. Acad. Wet. Amster- 

 dam, 685-705. Apr. 28. 



1907. Vinson, A. E. Some observations on the date. Plant World, 10: 259- 

 262. Nov. 



1910. Vinson, A. E. The Stimulation of premature ripening by chemical 

 means. Jour. Am. Chem. Soc, 32 : 208-212. Feb. 



1910. Vinson, A. E. Fixing and staining tannin in plant tissues with nitrous 

 ether. Bot. Gaz. 49: 222-224. Mar. 



VI. EXPLANATION OF PLATES 



f.s, fractured surface of tannin-mass ; 0, openings of canals on surface of 

 tannin-mass ; v, vacuole ; tm, tannin-mass ; tg, free tannin. 



Fig. I. Tannin-mass; internal and superficial structure of canals and cavi- 

 ties. Unripe, firm fruit. Variety " Taber." 



Fig. 2. Tannin-mass f rom a soft, ripe fruit. " Taber." 



Fig. 3. Portion of tannin-mass, showing, especially, the way in which the 

 canals open on the surface. Diospyros virginiana. 



Fig. 4. a, Portion of a canal with three adjoining cavities ; b, the same, 

 showing partial effect of internal pressures; c, final effect. D. virginiana. 



Fig. 5. End of an idioplast : a, b, c, separate tanning-masses shrunken by 

 glycerol ; a' , b' , c' , the same on adding water. " Taber." 



Fig. 6. a, Stream issuing f rom idioplast of an unripe fruit ; b, tannin-mass 

 flowing back, leaving free tannin behind; c, tannin-mass issuing as a partially 

 coagulated gel, and diffusing free tannin therefrom; a, b, D. virginiana; c, Taber. 



Fig. 7. Effect of ammonia on the tannin-mass (compare with fig. 13). 



Fig. 8. End of idioplast with two vacuoles, without tannin. Coarse granulär 

 alkaloidal reaction in, but not near the surface of, the tannin-mass. 



Fig. 9. Reaction of tannin-mass at the edge of a superficial depression, 

 which contains no free tannin. 



Fig. ig. Portion of completely matured idioplast, the protoplasm dead, but 

 showing no tannin reaction. 



Fig. ii. Extruding tannin-mass with opening on the surface. 



Fig. 12. Extruding tannin-mass, showing an apparently greater dififusion of 

 tannin from the torn edge of the cell wall. 



Fig. 13. Extruding tannin-mass, surrounded by a growing precipitation 

 membrane. 



Fig. 14. Precipitation of free tannin just beyond the surface of extruding 

 tannin-mass. o.i per cent. caflfein. 



Figs. 15, 16, 17, 18. Various forms of precipitation-membranes and figures. 



Fig. 19. Or-d, Four stages of a growing tubulär precipitation-membrane, 

 the final shape of which (19, d) was produced by a current of water flowing 

 in the direction indicated by the arrow. 



