THE THREE CONDITIONS OF THE SEED 31 



resting state some seeds on being dried in air after reaching 

 the point of germination are heavier, others are lighter, and 

 others remain unchanged. Various disturbing causes that 

 would be likely to come into play in the course of the experi- 

 ment here suggest themselves ; but they can usually be 

 eliminated ; and, as shown in Note 2 A, none can account 

 for the great contrast in the behaviour of the seeds of 

 Guilandina bonducella and Faba vulgaris, where in the one 

 case there is a gain of about 6 per cent., and in the other a 

 loss of 2 per cent. 



However, as will be seen in the table, as well as in the 

 illustrations given above, these marked differences are displayed 

 by two distinct types of seeds, the impermeable as represented 

 by Guilandina bonducella^ and the permeable as exemplified by 

 Faba vulgaris. A good deal of this contrast, therefore, lies 

 behind the distinction between permeable and impermeable 

 seeds ; and its significance will become evident only after a 

 detailed consideration of those two types of seeds. 



The second additional proof that the swelling of a seed for Second, that 

 germination is essentially concerned with absorption of water relation! of 

 might seem to be included in the first ; but there we were c ats, kernel, 



albumen, and 



concerned with the seed in its entirety, whilst here we are embryo are 



dealing with its parts. The proof lies in showing that the same in the 



absolute weight of parts that obtains in the resting seed is in !fte r swell- 



the main preserved in the seed that has been dried after swelling in r for & er - 



r r- MI i-ji_i minationas 



tor germination, .bour illustrations supplied by leguminous they are in 

 seeds are here given ; but for full details on this subject se ed reS 

 reference must be made to Note 3 of the Appendix. I am 

 here giving the results of observations on single seeds, and 

 these are compared with the average weights of the parts in 

 resting seeds of about the same size. The parts of the swollen 

 seed were separated in the wet state and allowed to dry in an 

 ordinary room. The small changes in weight that actually 

 occur have a significance which is alluded to in a later page ; 

 but they are not such as to materially affect, the general 

 conclusion to be drawn from the comparisons. The first two 



