CHAPTER VIII 



A LAST WORD ON THE HYGROSCOPICITY OF SEEDS 



The seed's capacity of regaining from the air the water driven 

 off by exposure to a temperature of ioo° C, has been discussed 

 pretty much in the order in which the investigation has been 

 pursued. We have plodded on without always knowing where 

 the road was leading to, diverging first to one side and then to 

 the other, feeling our way often in the darkness, until at length 

 we have stumbled on a clue that throws much light on the 

 whole inquiry. The principle of Berthelot only came under 

 our notice when the investigation was far advanced, and of 

 course it would be possible to recast much of what has been 

 already written in the light now displayed to us. But it has 

 been found easier to present the work in the stages in which it 

 shaped its course and to introduce this principle much as the 

 romance-writer produces his climax towards the end of the 

 story. 



In my last word on the subject of permeable and imperme- 

 able seeds and the contrasts they present, I therefore view the 

 whole matter from a different standpoint. Up to now the im- 

 permeability of seeds has been the most conspicuous feature in 

 the discussion ; and most of the results obtained shaped them- 

 selves in one way or another in some relation to this quality. 

 Here I propose in a few pages to make the water of hygro- 

 scopicity the centre-point of the discussion. The hydratation 

 of all living vegetable matter may be thus simply stated. There 

 is the water that is lost when the materials are allowed to dry 



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