*ECT. I. CONDITIONS. 1 



presented to the germinating seed in an uncom- 

 bined state, incontrovertible. 



In all cases of germination, however, the pre- And ai- 



n f A l wa YS !>- 



sence of oxygene is necessary. Jbor even of those ce sary, 

 seeds that germinate in water, the germination takes 

 place only in consequence of the oxygene which the 

 water contains in an uncombined state. Saussure 

 introduced into a recipient placed over mercury, 

 a quantity of boiling water, into which, when it 

 was cooled down to a proper temperature, he in- 

 troduced also some grains of Peas, together with 

 a few seeds of Alisma Plant ago, and Polygonum 

 amphiblam. They exhibited no symptoms of ger- 

 mination when the quantity of water introduced 

 was not more than seven or eight times the weight 

 of the grains. But when the weight of the water 

 was an hundred or two hundred times more than 

 that of the grains, they then germinated ; and the 

 radicle was developed in proportion to the quantity 

 of water employed. The solution of the pheno- 

 menon is as follows : the boiling had not yet de- 

 prived the water of the whole of the oxygene it 

 had originally contained in an uncombined state ; 

 and it required but to be presented in sufficient 

 abundance to effect the germination of the seed.* 



But the period necessary to complete the pro- Period of 

 cess of germination is not the same in all seeds, I 

 even when all the necessary conditions have been 

 furnished. Some species require a shorter, and 

 * Sausfure, sur la Veg, chap. i. sect. i. 



