66 Practical Farming 



How Plants We have said that the green granules in 



Get Food ^j^g living matter of the plant cells known as 



chlorophyll, are one of the most important 

 things in the Hfe of the plant. And the green color 

 is essential to their activity. Let a potato sprout in 

 the dark and you may take the section of the stem and 

 find that the granules are there, but have not taken 

 on the green color. Find two potatoes of exactly the 

 same weight. Let one sprout in darkness and keep the 

 other one from sprouting till the sprouted one has made 

 long white shoots. Then thoroughly dry them both as a 

 chemist would dry them and you will find that the sprouted 

 one has not gained anything in dry matter. There has 

 simply been a transfer of the materials stored in the potato 

 to a different form, and no real growth has been made. 

 Now take two similar potatoes and let one of them sprout 

 in the full light of the sun till there have been developed 

 strong green shoots, then dry both again, and you will 

 find that the potato that has made green sprouts has 

 gained a little in dry matter. 



Hence we find that in some way the green color is an 

 important thing in the plant life. By far the larger por- 

 tion of the structure of all plants comes from the air, over 

 95 per cent. How then does the plant get the material 

 for growth from the air? In the leaves of every plant, 

 especially on the underside of all leaves, there are numerous 

 openings of microscopic size, on each side of which there 

 is a cell something Hke a Up, and these two Hps constitute 

 really the mouths of the plant, for they are capable of 

 opening and closing just as we can open and close our 

 lips. They open between the loosely arranged cells in 



