22 CROP GROWING AND CROP FEEDING 



them. If you sprout a seed in sand, and when the roots have developed, take 

 it carefully from the sand and gently wash the roots, you will find that the 

 root hairs are covered with fine particles of the sand, closely adhering to them. 

 This close adhesion of the root hairs enables them to absorb all the moisture 

 that surrounds the soil particles as a film, and enables them to get an amount 

 of moisture from an apparently dry soil, that is surprising to those who have 

 not studied that matter closely. There is also evidence that the root hairs do 

 to some extent, exert a solvent influence on matters in soil otherwise insoluble. 



THE COURSE OF THE SOIL WATER IN THE PLANT. 



There is a direct connection between the roots branching in the soil, with 

 their myriad of absorbing hairs, and the leaves on the top of the plant. In 

 our trees and woody plants, this course is through the youngest sap wood, and 

 in herbaceous plants like corn, it is through the pithy soft tissue. Anyone 

 who has observed a corn stalk, has seen that through the soft part of the stalk 

 there are a multitude of threads. Observing a cross section of the corn stalk 

 under the microscope, we see that these threads are really tubes, or elongated 

 cells, with thickened walls, and in the growing state of the plant, the walls of 

 these cells are always saturated. As the leaves branch off, some of these tubu- 

 lar threads branch into the leaves and form the framework, or what we call the 

 veins of the leaf. It is through these fibres that the sap water reaches the 

 leaves, and it is in the leaf where all the wonderful changes are made by which 

 new material for growth is formed. Then after the material for growth is 

 made it is carried wherever there is call for material through the youngest 

 cells of the growing bark, and all the material for growth of top and roots 

 comes from the leaves. 



Twist a wire tightly around the stem of a growing plant, and you will 

 see that the growth is coming downward from the leaves. The stem swells 

 above the stricture, and if it is long continued the path for the ascending sap 

 water is finally cut off, and the branch will perish, with a swollen base 

 formed from the materials that were taken in from air and soil before the 

 wire was placed there. 



There was an old notion that the sap goes up in the spring and down in 

 the fall. The fact is, that there is no circulation in plants that can be com- 

 pared with the circulation of the blood in animals. The sap that rises in the 

 trees in the spring is simply sap water in which the food of a mineral nature 

 for the plant and the nitrogen for the living matter is dissolved, and the 

 only descent is that of the formed material for growth. 



