ADDITIONAL EVIDENCE 121 



bared kernels of impermeable seeds. This has already 

 been noticed in the case of the seeds of Guilandina bondu- 

 cella in Chapter IV, where it is shown that after the first 

 gain of 13 per cent, the weight began to diminish slowly, The degree 

 though even after two years there was still an excess of manYiiceof 

 3 per cent., allowing for the hygroscopic variation. This theexcess 

 loss of the excess weight in time is not at first sight easily acquired by 

 explained. However, since the bared seed in absorbing meable 

 water from the air assumes the r61e of the kernel of a ^^^"®- 

 permeable seed, it is likely that light may be thrown on it 

 when we come to discuss the final fate of permeable seeds 

 in time. 



On the other hand, a different indication is ofi^ered where 

 the seed is punctured or filed, when the gain in weight takes 

 place very slowly. Thus it is shown in the table of results 

 given in Chapter IV for punctured seeds of Guilandina bondu- 

 cella that the punctured seeds occupied some months in reaching 

 the maximum excess weight of 10 or 11 per cent., and even 

 after two years were still 7 or 8 per cent, heavier than before 

 they were punctured or filed. 



However, experiments of this kind being always con- 

 ducted under dry conditions are by no means imitations 1 

 of what occurs in nature, though they indicate latent 

 properties or potentialities of impermeable seeds. In the 

 home of the plant, such a seed, if deprived by some defect 

 or injury of the proper protection of its impervious cover- 

 ings, would either pass on to the germinating stage or 

 would become mouldy and decay. But it is only with 

 those seeds where there is a great increase in weight, such 

 as occurs with the bared kernels of Guilandina bonducella, 

 that one can test the duration of the excess weight by 

 eliminating the; ordinary hygroscopic reaction of 2 or 3 per 

 cent. Impermeable seeds, when deprived of their coats, 

 gather weight during the first week or two independently to 

 some degree of the atmospheric conditions. After this they 

 respond normally to the changes in the hygrometric state of 



