close pile like velvet, and thus 

 enormously increasing the surface 

 through which water can be taken 

 up. It has not yet hardened and 

 become discoloured. Long before 

 this change has taken place the 

 hairs drop off, and the portion of 

 the rootlet on which they grew is 

 comparatively useless for purpose 

 of absorption. Meanwhile the tip 

 of the rootlet has pushed further 

 into the soil. New root-hairs have 

 arisen on the newly-grown length, 

 and they in their turn fulfil the 

 duty required. The actual grow- 

 ing tip itself absorbs but little. 

 It is covered with a protective cap 

 of tissue, which is constantly 

 wearing away and as constantly 

 being renewed, and which serves 

 to protect it from actual contact 

 with the particles of the soil 

 through which it is forcing its 

 way. 



6. All these facts can easily be 

 demonstrated. A rape seedling 

 carefully taken up exhibits the 

 naked apex of the main root and 

 the zone of root-hairs at some dis- 

 tance behind covered with adherent 

 particles of soil. If these be 

 gently washed off the close pile 

 of hairs comes distinctly into view. 

 Each hair is hollow and opens 

 gure i. directly into some one cell of the 



root-wall, even as the finger of a glove opens into the 



cavity left for the palm of the hand. 



7. Then it would seem that the transplant-trees one is 

 accustomed to receive, with no ball of their original earth 



Figure 1 .Root-hairs of a young wheat-plant. 



B 2 



