GROWTH OF THE SEED. 417 



ferent habits from those of the parent plant. The 

 organizable matter which is given by the parent to 

 the offspring in this case, probably exists in the cot- 

 yledons of the seed, in the same state as in the 

 alburnum of trees, and, like that, it apparently un- 

 dergoes considerable change before it becomes the 

 true circulating fluid of the plant. In some it 

 becomes saccharine, in others acrid and bitter, during 

 germination. In this process the vital fluid is drawn 

 from the cotyledons into the stem of the plumule 

 or bud, through vessels which correspond with those 

 of the bark of the future tree, and are indeed 

 perfect cortical cells. From the point of the stem 

 springs the first root, which at this period consists 

 wholly of bark and medulla, without any alburnous 

 or woody matter; and, if uninterrupted by any 

 opposing body, it descends in a straight line toward 

 the centre of the earth, in whatever position the 

 seed has been placed, provided it has been permitted 

 to vegetate at rest. 



' " Soon after the first root has been emitted, the 

 stem elongates, and, taking a direction diametrically 

 opposite to that of the root, it raises, in a great 

 many kinds of plants, the cotyledons out of the soil, 

 which then become the seminal leaves of the young 

 plant. During this period the young plant derives 

 nourishment almost wholly from the cotyledons, or 

 seed-leaves, and if these be destroyed it perishes. 

 " The bark of the root now begins to execute its 



