CH. I. 



BY THE SURFACE OF THE ROOTS. 



23 



its leaves and the end of its main root, it will remain 

 alive and continue to grow, even after the last inch of 

 its main root is dead and dry. But the leaves will 

 sometimes droop at first, unless they also have access to 

 the water by their foot- stalks. Eadishes have many 

 side-roots (a new fact, perhaps, to most physiological 

 writers)^ and I have found these results to be the 

 same, whether the side-roots are taken off or left on, 

 and whether the end of the main root is left in the 

 water or out of it ; or whether the end of the main 

 root is cut off or left on the plant, or if the lower half 

 of the radish is cut off, or if it is cut off within half an 

 inch of the neck. When radishes have once been well 

 saturated with water, they will remain alive for a long 

 time under any circumstances. 



If a radish is placed in a narrow-necked bottle, 

 such as an eau de Cologne bottle, the absorption of water 

 is very apparent by the decrease of water in the neck 

 of the bottle. If the bottle is kept fiUed, so as to give 

 all the radish the power of absorbing laterally, the 

 radish will live. If the bottle is not kept filled, the 

 radish will fade as the level of the water sinks to the 

 immature parts of the radish. 



On the 13th of April, 1850, I instituted three 

 experiments similar to these ; but in earth instead of 

 water. The results were equally favourable to the 

 position that the absorption of nutriment by roots is 

 through the medium of their mature parts, and not 

 through the medium of their immature ends. 



