1909.] Coverings of the Seeds of Hordeum vulgare. 91 



Table VII. 





Percentage of water absorbed. 



2 days. 



4 days. 



6 days. 



8 days. 



Ammonia — 















53 -5 





70 -1 



74 -8 



77 -2 



x 



53 -9 





68 -5 



73 -5 



74 -2 



i 



51 -5 





65 -9 



72 -3 



72 -2 



Sodium chloride (control) — 













Normal solution 



29 -4 





32 2 



33 -3 



34 -6 



i » » 



32 -2 





37 -1 



39 -4 



40-4 



A 



35 -1 





41 7 



45 -7 



48 -4 





43 -1 





55 -6 



64-1 



68 -3 



Non-electrolytes. — As previously pointed out, cane-sugar and dextrose 

 resemble the electrolyte sodium chloride in their power of diminishing the 

 extent to which water is absorbed by the seed system, and in being unable to 

 penetrate the seed-covering. 



Experiments made with a number of non-electrolytes of much lower 

 molecular weight than the sugars show the behaviour of these to be com- 

 parable with that of weak electrolytes. 



The following table contains the results of experiments with volume normal 

 solutions of ethyl alcohol, aldehyde, acetone, and ethylic acetate. For purposes 

 of comparison, the results obtained at the same time with water and with 

 volume normal solutions of acetic acid (representing a freely diffusible solute) 

 and of sodium acetate (representing a non-diffusible solute) are given : — 



Table VIII. 



Solute. 



Percentage of water 



absorbed. 



Ethyl alcohol 



74 -0 



Aldehyde 



70-6 





72 -7 



Ethylic acetate 



73 -1 



Acetic acid (control) 



73 -8 





78 "2 



Sodium acetate (control) 



39 -8 



The results indicate that water is absorbed by the seed-system from solutions 

 of alcohol, aldehyde, acetone, and ethylic acetate approximately as it is absorbed 

 from that of acetic acid, or when in contact with water alone. 



Very similar results were obtained on using weight normal solutions. 



Experiments in which seeds were placed in contact with alcohol, aldehyde, 

 acetone, and ethylic acetate in the anhydrous condition have shown that these 



