Howard : Tannin cells of persimmons 



573 



The above facts show very convincingly why it is that in eating 

 partially ripe persimmons they first produce a fine sweet taste, 

 while it usually takes about half a minute for the taste to detect 

 any astringency ; this of course being due to the fact that the 

 saliva, being a liquid of low osmotic strength, causes in a few sec- 

 onds a swelling and rupturing of the tannin cells and finally the 

 consequent development of astringency. Fruit-pulp in this stage 

 of development if mixed with water changes only slowly. When 



r 





Figure 6. Tannin cells after bursting, showing tannin globule on side of cells. 

 X25. 



rupturing and contact with water has finally occurred there appear 

 after a short time, even to the naked eye, whitish particles. These 

 on further examination are found to be the expelled cell-contents, 

 which on coming in contact with abundance of water have assumed 



a white granular condition. 



The writer has also observed that solutions considerably stronger 

 than those necessary to maintain equilibrium will produce a shrink- 

 ing of the cell-contents. This is of course what might be naturally 

 expected when the cause of the swelling is considered. 



