THE VEGETABLE KINGDOM. 515 



the young plant, for this could only find in the ground 

 food too active or too coarse for its yet undeveloped 

 tissues. Then when these vegetal)le mammfe, as Bonnet 

 called them, have accomplished their function, and when 

 the roots are vigorous enough to nourish themselves, the 

 part of these organs being played out, they fade and fall. 



Such is the last phase in the evolution of the young 

 plant. 



At the same time that these different vital actions are 

 carried on, the germination is the theatre of important 

 chemical phenomena. For its accomplishment it imjieri- 

 ously demands a certain amount of warmth, water, and 

 air. If one of these factors be wanting, this first manifes- 

 tation of life becomes an impossibility. At the tempera- 

 ture of zero all vegetation ceases. 



When cold fastens upon seeds it preserves them for an 

 indefinite period of time, just as it preserved the compan- 

 ions of Bilbao, the discoverer of the South Sea, whose 

 corpses were recently found in the snows of the Cordilleras; 

 and as it preserved the remains of the antediluvian elephants 

 and rhinoceroses, the skeletons of which, still enveloped in 

 their flesh, were discovered in the ices of Siberia. 



The course taken by the water, Avhich is to soak into 

 the grain and prepare the Avay for its evolution, is not 

 always the same. 



In seeds which have a coriaceous husk, not easily per- 

 meable by moisture, the liquid enters by the umbilicus. 

 Poncelet and De CandoUe proved that all the outer surface 

 of these seeds might be covered with wax, and yet that 

 would not prevent them from germinating if the precau- 

 tion Avere taken of not covering the umbilical cicatrix. 



In seeds the skin of which is soft and easily imbibes 

 water, such as those of the haricot bean for instance, it is 



