82 THE LIFE OF THE PLANT 



investigation will probably enable us to discover the 

 immediate cause of these phenomena. As a matter of 

 fact the property of conserving during many years the 

 capacity for germination should not strike us as strange. 

 If a seed does not contain the necessary water, or is 

 isolated from atmospheric influences by its membranes, 

 or in some other way one or other of the conditions for 

 chemical changes is therefore not fulfilled, it is difficult 

 to imagine what influence time can have, once the possi- 

 bility of mechanical injury is removed. There are 

 indubitable facts which prove that seeds taken out of a 

 herbarium, in which they had lain for more than a 

 hundred years, germinated very successfully. Another 

 illustration frequently cited is the so-called ' mummy 

 wheat ' which remained in Egyptian tombs for more 

 than a thousand years ; but this case is not authenti- 

 cated. The capacity for remaining in a dormant state 

 during so many years without losing the power of 

 reviving is not the exclusive property of seeds alone. 

 Many of the lowest, microscopic animals, when in the 

 condition of a dry powder, can be kept for years in that 

 state, and revive again as soon as they are moistened 

 with water. The other extreme, the loss within a few 

 days of the capacity for germination, is harder to 

 explain. The facts here seem rather to bespeak some 

 special vitality in the seed which is gradually lost. 

 Yet such facts are not beyond explanation nor without 

 analogy elsewhere. Coffee beans, for instance, have 

 their nutrient material stored up in great part as 

 cellulose, which makes their endosperm hard and horny. 

 Very probably the solubility of this endosperm varies 

 greatly in course of time, since cellulose is able to 

 undergo such changes even outside the organism. 

 Freshly precipitated cellulose, or cellulose kept in a 

 moist condition, easily dissolves in a certain reagent, 

 but the same cellulose when dried and forming dense and 

 horny masses becomes almost insoluble. Possibly some- 



