42 



STUDIES IN SEEDS AND FRUITS 



much on the imperfection of the method as on the failure of 

 the seeds, since, as above remarked, experiment has established 

 the ability of certain seeds to withstand for some hours a 

 temperature of ioo° to 120° C. However, the original 

 purpose of this experiment has been served in demonstrating 

 the protection an impervious covering affords against extreme 

 thermal and hygrometric conditions. 



Very different is the behaviour of the permeable seed 

 under the strain of a high temperature, a difference which its 

 hygroscopicity would lead one to expect. Permeable seeds 

 give up their moisture in the oven almost as readily when 

 protected by their coverings as in the exposed condition. 

 Since we have already seen in the chapter on type seeds that 

 with such seeds the coats merely restrain but do not prevent 

 the hygroscopic reaction of the kernel, the results given below 

 are such as we should have looked for. 



Table showing the Influence of their Coverings on xfiE Behaviour 

 OF Permeable Seeds when exposed for two Hours to a Temper- 

 ature OF 100° TO 110° C. 



(Two samples of each kind of seed were employed, one with the seeds entire, the 

 other with the seeds cut across so as to be deprived of the protection of their coverings. 

 The seeds were eight or nine months old, the samples of the peas weighing loo grains 

 and of the others 200 grains. The results are given in percentages. ) 



By contrasting the results above tabulated with those given 

 a few pages back for Entada scandens and Guilandina bonducella, 

 where the seeds were exposed to the same test, we can frame 

 a numerical estimate of the difference in the degree of protec- 

 tion against high temperatures which the coverings offer in the 



