iQii] Francis Ernest Lloyd 21 



sure on the inside of the cell-wall. Whenever the canals and cavi- 

 ties, therefore, are absent from the tannin-mass, when in its defini- 

 tive condition, this must have undergone a period of swelling during 

 ripening. It is of importance to record at this point that the tannin- 

 masses in a fruit acted upon for three days by acetic acid vapor 

 (Oct. 17, 1910) remained permanently in the swollen condition 

 and, after three months (Jan. 25, 191 1), still show no change. 

 They behave in this way also in some fruits not treated, while in 

 others of the same variety they passed into the shrunken condition. 

 Shrunken and swelled tannin-masses occur in the same fruit. At 

 this time the cells are dead, but the tannin-mass may swell on the 

 addition of water, and the expression of free tannin, as described 

 beyond, may take place, in a manner identical with that in a living 

 cell. 



The swelling, when it takes place, appears to occur at the time 

 when the middle lamella is broken down by digestion. It is now 

 that the fruit becomes mushy or even watery, the parenchyma cells 

 being at best loosely attached, or literally floating in the fluid. Des- 

 pite the high osmotic equivalent of this fluid (for it has the con- 

 sistence of thick syrup), the tannin-masses absorb water, thus ac- 

 counting for the swelling. That the tannin-masses, if they are 

 capable of swelling at all, will do so in a normal Solution of potas- 

 sium nitrate, accords with this Observation. 



The fact that during ripening the tannin-mass gradually loses, 

 up to a certain limit, the power of swelling is a remarkable fact. 

 It may be explained, perhaps, by the progressive combination 

 with tannin, just as we may imagine a body of cellulose becoming 

 less capable of Imbibition by an increase in the amount of fats, as 

 occurs in the formation of a cuticle. But it remains to obtain ex- 

 perimental proof that this sort of a change can be brought about 

 by tannin.^ ^ Here it may be said that the tannin-mass swells much 

 more in ammonium hydroxid solution^^ (flg. 7) than in water, 

 though finally in the definitive condition there is little or no ob- 

 serv'able increase in dimensions. 



The behavior of the soluble tannin. Correlated with this 



" Gelatin alone and gelatin-tannin offer analogous conditions. 

 " Weak ammonium hydroxide Solution is, apparentlj', as affective as a streng 

 Solution. 



