they take up this food obtained from the soil. It is im- 

 possible to go into details in this regard, but it is one of 

 the most difficult of plant operations for us to understand. 

 The roots of plants have more than one duty to perform — 

 they hold the plant steady in the soil; if fleshy roots, they 

 are a kind of storehouse for feeding the growing plant, 

 as little bean plants are fed; but their main duty after all 

 is to absorb moisture — this water being laden with the 

 mineral salts which are the main food of the plant. In 

 order to absorb this moisture the roots send out tiny root 

 hairs which act as mouths to drink it in. There are so, 

 many of these root hairs and they are so small that they 

 can take up moisture from every little particle of soil 

 which they are able to get at, until the soil is as dry as 

 dust. These little root hairs never grow into roots them- 

 selves, but die off when no longer needed on the old and 

 woody roots. 



Now the moisture taken up by the root hairs would 

 do the plant no good if it could get no farther, so the 

 food burdened water is carried up through the woody tis- 

 sue of the plant to the leaves. It travels up through the 

 youngest woody ring in a tree; in corn it is carried up 

 through the thread-like fibers which can be seen in the 

 pith; in plants having netted veined leaves and herb-like 

 growth, it ascends in the tissue between the pith and the 

 bark. Having reached the leaves that portion of the wa- 

 ter no longer of use to the plant is evaporated and the 

 mineral salts are left behind to be used as food. But you 

 must not understand that the soil is the only source from 

 which plants derive food. Some plants (a family of them 

 called Leguminosae) get their nitrogen by means of their 

 roots from the air and not as others do from the soluble 

 salts in the soil. All plants get the carbon which they so 



