78 



STUDIES IN SEEDS AND FRUITS 



Exposure to 

 a tempera- 

 ture of 100° 

 C. does not 

 prevent a 

 bared imper- 

 meable seed 

 from increas- 

 ini; its 

 ori^nal 

 weight by 

 absorbing 

 water- 

 vapour from 

 the air. 



Both the 

 kernel and 

 'the coats of 

 an imper- 

 meable seed 

 retain their 

 absorptive 

 capacities in 

 air after ex- 

 posure to a 

 temperature 

 of 100° C. 



accident that first disclosed to me the ultra-dryness of imper- 

 meable seeds. After weighing a sample of kernels of Guilan- 

 dina bonducella which had just been exposed in the oven for a 

 short time to a high temperature and had lost 8 per cent, of 

 its weight, I unwittingly left it over-night in the pan of the 

 balance, and was surprised to find that it was between i and 2 

 per cent, heavier than before it was placed in the oven. During 

 the night it had regained all the water driven off by heat and 

 something more. 



The results of numerous oven-experiments on this and 

 other impermeable seeds go to make it evident that the 

 capacity of such a seed to considerably increase its weight 

 when exposed in a broken condition to the air is but little 

 aflFected by first subjecting the material to a temperature 

 of ioo° to 105° C. for an hour or two. If, to take an 

 actual case, a seed on being broken up increased its weight 

 after three or four days' ordinary exposure on my table 

 from 100 to 113 grains, it made but little ultimate diflfer- 

 ence whether or not its weight had first been reduced 

 to 93 grains through the loss of water in the oven. I 

 will here appeal again to the behaviour of the seeds of 

 Guilandina bonducella^ reserving for a subsequent chapter the 

 detailed treatment of this matter as regards other imper- 

 meable seeds. 



There are given below the results of two actual experi- 

 ments, the first in Jamaica and the second in Grenada, on the 

 effect of exposure to a temperature of 100° to 105° C. on the 

 absorptive capacity in air of the broken seeds of this plant. 

 In the second experiment the seed-coats were separated from 

 the kernels, thus enabling one to differentiate between the 

 bared seed and its coverings in this respect. Since the 

 seeds in this case were equally divided between the samples, 

 we are able to compare the absorptive behaviour in air of 

 truly mixed materials under these different conditions. We 

 thus perceive that in the slight influence of exposure to 

 high temperatures on their absorptive capacities both the 



