HOW THE ROOT GETS FOOD FROM THE SOIL 15 



same way sugar and other substances in the root hair 

 draw in the water, overcoming the force with which the 

 soil particles hold fast to it. As fast as the water 

 is taken away from a particle, more water flows to it 

 from particles near by, and so these also give up their 

 water to the root hairs. 



FIG. 9. Seed covers floating on water. In each is placed three or four 

 crystals of sugar, which draw the water through the cover and soon dis- 

 solve. . This does not happen in the covers placed on the dry glass strip. 



What are " feeding roots"? Root hairs are not 

 found all over the root, but only at the ends of its finest 

 branches (figure 10). Each root hair lives but a short 

 time. It does not grow into a rootlet, but withers and 

 falls away. New root hairs are continually formed 

 at the ends of the fine roots. The root hairs increase 

 the absorbing surface of these roots from seven to 

 seventy times^.- 



These fine roots are known as " feeding roots' 7 be- 



