CH. I. BY THE SURFACE OF THE ROOTS. 19 



too mucli to suppose that, in the ordinary course of 

 nature, the sap should perpetually flow both ways at 

 once in the same channel. 



As this question is of vital importance in trans- Experi- 



^ ments m 



planting, I will state the results of several experiments 

 in support of these opinions. To begin again with the nou?- 



seedling. In March, 1836, 1 made some horse-chestnut J-oote tm 



seeds grow in water, in my barrack-room, and found come^^ 



woody, but 



that when the root was cut off when it was several by the seed, 

 inches long, the plant would still grow, and would 

 continue to throw out fresh roots as fast as they were 

 cut off. The existence of the plant was evidently 

 independent of the root. The reason is, that unripe, 

 that is un woody, roots are incapable either of absorb- 

 ing or of transmitting sap ; but receive their own 

 nourishment from above, — in this case, from the seed. 

 Consequently, whenever I divided a plant from its 

 seed, it died, though the root was perhaps twice the 

 length of the plant, and though leaves were developed 

 on the plant. Yet, when I allowed the seeds to remain 

 attached to the plants till the roots had become woody, 

 the plants grew in water for years. Moisture is taken 

 up by absorption from the surface of the seed; the 

 elaboration of the sap is entirely in the seed, and passes 

 through the bands which unite it to the seedling, for 

 the growth of the plant upward and of the root down- 

 ward ; and the seedhng is entirely dependent on the 

 seed for its life and for its growth till the roots have 

 become woody. Still farther to prove this, I have 



c2 



