THE THREE CONDITIONS OF THE SEED 19 



seed, and cannot be compared with the three previous stages 

 (characterised by a passive vitality), which may be fitly 

 termed the shrinking, resting, and swelling stages. The 

 germinating stage may never be reached, since the absorption 

 of water that brings about the swelling of the resting seed is 

 more a mechanical than a vital process, and may or may not 

 terminate in the growth of the embryo, which is the essential 

 feature of germination. 



The shrinking stage is characterised by loss of water, the The shrink- 

 swelling stage by absorption of water, and the intervening sweUing 

 resting stage by a suspension, more or less complete, of the confermsd 

 drying process and by a greater or less state of passivity on the with water- 

 part of the embryo. It is with these three stages that we are water-gain, 

 now concerned, that of germination not coming within the 

 field of our inquiry. The shrinking of the pre-resting seed 

 and the swelling of the resting seed are the two processes to 

 be now discussed. It is the shrinking process that ushers in 

 the rest-period, and It is the swelling process that prepares the 

 seed for germination. In the first case there is water-loss, in 

 the second, water-gain ; and it may safely be assumed that as 

 a general rule we are here concerned mainly with these pro- 

 cesses, the proofs of which are discussed later on in this 

 chapter. 



Here the balance becomes the instrument of investiga- Method of 

 tion ; and it is to the changes in weight in the different '°^""7' 

 processes that appeal is chiefly made. We deal at first 

 with the entire seed, the independent behaviour of seed- 

 coats and kernel being separately discussed in Chapter IX. 

 The weight of the resting seed is taken as one, whilst the 

 maximum weights of the pre-resting seed before shrinkage 

 begins and of the swollen seed on the eve of germination 

 are expressed in ratios. Thus, to take one of the very 

 largest of leguminous seeds, that of Entada scandens : a seed 

 which weighed 1004 grains in the soft, swollen condition 

 weighed 408 grains in the contracted resting state ; and sub- 

 sequently, when on the eve of germination, it Increased 



