THE THREE CONDITIONS OF THE SEED 21 



ing for germination. This method is more practicable and has 

 been frequently employed, and, although open to the same 

 objection as regards the premature separation of the seeds from 

 the parent plant, it is easy, by the use of normal seeds as a 

 check, to exclude those where the shrinkage has been irregular. 



A third method employed at times, especially for the 

 shrinkage, has been to compare the average weight of a 

 number of full-sized pre-resting seeds or of seeds swollen for 

 germination with the average weight of a resting seed. This 

 is exposed to the objection that seeds vary much in weight, an 

 objection losing some of its force if a large number of seeds 

 are used. 



With reference to the determination of the maximum 

 weight of the swelling seed, it would appear difficult to 

 ascertain where simple absorption ends and germination, or 

 active growth within the seed, begins. In practice, however, 

 this difficulty does not often arise, and it can usually be met 

 by frequently weighing the swelling seed up to the beginning 

 of germination, an approximate estimate being alone expected. 



By way of opening the subject I wiU first deal with my obserratioiis 



experiments on single seeds or sets of seeds, where the history ght^ing 



has been followed for each seed from its soft, swollen pre- and swelling 



• J II- ratios 01 



resting condition through the rest-period on to the swelling single seeds 



... • ^- T Li- or sets of 



Stage terminating in germination. 1 possess such a continuous seeds indi- 



series of observations for the seeds of four leguminous and one ^^^^J^ 

 malvaceous species. As given in the tables subjoined, these shriridngis 

 data affijrd an early indication of a principle which will figure sw^gfor 

 prominently in subsequent pages, that the water lost in shrink- ser™"**'""- 

 ing is regained in swelling for germination. Thus, if a full- 

 sized pre-resting seed weighing 100 grains shrinks to 40 grains 

 during its drying, and after a rest-period of some months . 

 regains its original weight of 100 grains when swelling for 

 germination, we have data directly indicating such a principle. 

 There is much in these tables that will be elucidated as the 

 work proceeds ; but I may here point out that the behaviour 

 of the imperfectly shrunken seeds of Guilattdina bonducella there 



