iQii] Francis Ernest Lloyd 27 



in the cell wall. The escaping tannin is precipitated and forms 

 membranes of a variety of forms ; tubes of varying diameter, hemi- 

 spheres, spheres, chalices and various combinations (figs. 15-20). 

 Their growth may be watched for a half-hour or longer, until the 

 free tannin is exhausted. Reagents produce tannin reactions in these 

 membranes. They may be preserved for future examination by 

 adding a little weak glycerol, and beautiful preparations (though 

 easily destroyed) may be made by judicious staining with methyl 

 blue (fig. 20). If a growing tube comes into contact with the 

 surface of the slide or cover, it will spread out to form a wider, 

 flat tube. The direction of growth may be controlled by causing 

 a light current in the surrounding water (fig. 19), though the for- 

 mation of a membrane will cease if too much water be added. 

 Through these tubes there may be observed no movement of gran- 

 ules, though that there is a movement of tannin in Solution is a 

 certainty. There is thus afforded a demonstration that the free or 

 soluble tannin escapes from the tannin cell as a Solution. 



These events appear to be entirely independent of the living 

 condition of the protoplasm. I have produced them two months 

 later by the proper treatment of the pulp of fruit killed with 

 acetic acid. The precipitation tube figured grew at the rate of 

 15 microns in 11 minutes, measured by an eye-piece micrometer 

 (fig. 21). These curious precipitation membranes are formed of 

 tannin which would never in the ordinary course of events be 

 rendered insoluble within the tannin cell. I have found evidence, 

 however, that, during ripening, this tannin (the excess over that 

 which the tannin-mass can take up), is expelled by the temporary 

 swelling of the tannin-mass and is thus forced out into the inter- 

 cellular Space now occupied by pectose, and combines, more or less 

 completely, with this. Macroscopically, this may be followed in 

 pulp which has been placed in a glass vessel, when without any 

 addition of water a white substance is seen to form, That this 

 occurs also in the fruits which are left entirely undisturbed, I have 

 shown by allowing them to overripen without being touched or 

 removed in any way.^^ 



In the course of some days, the tannin-mass swells sufficiently 



"The accidental intercellular tannin is not due to this (Lloyd, iQii). 



