GERMINATION. 71 



this softens the structures soon to be brought more ac- 

 tively into play, dissolves or renders soluble others ne- 

 cessary for the further prosecution of the process, and 

 offers by its decomposition the necessary element, 

 oxygen. 



11. This fluid has found entrance into the seed by 

 imbibition through its testa ; though in some cases, per- 

 haps, where this is very hard and not easily penetrable, 

 it passes through the micropyle ; the quantity imbibed, 

 in some experiments of Edwards and Collin, was found 

 to be equal to the weight of the seed itself. 



12. In 1777, Scheele stated that the presence of 

 oxygen was absolutely necessary for germination to take 

 place, and that the air in which seeds were made to 

 grow underwent no change of volume, but that its 

 oxygen disappeared and a quantity of carbonic acid was 

 produced equal to it ; since which time the numerous 

 experiments which have been made leave no doubt upon 

 the mind of the necessity of oxygen being taken in by 

 the seed, and likewise of the expulsion of carbonic acid 

 from it. 



13. Till lately it was thought that this oxygen was 

 obtained only from the atmosphere itself, but it has 

 been shown by Edwards and Collin that it is also by 

 the decomposition of water that this element is pro- 

 cured ; and besides this fact of the decomposition of 

 water by the seed during germination, they have like- 

 wise stated that the other element of it, hydrogen, is 

 absorbed by the seed either wholly or in part, and which 

 has beeft confirmed by Boussingsalt. 



14. Now it must be remembered that the seed before 

 germination contains a considerable quantity of carbon 

 andfecula, and that the power of losing to a certain 

 extent this carbon, constitutes a preliminary step in the 

 process of germination, whilst the conversion of the 

 fecula into saccharine matter goes on almost synchro- 

 nously with it. 



15. From what has lately been shown, and accordant 

 with what we have stated, we may say that during 



