426 Junior Naturalist Monthly. 



rays of light become more vertical — more up and down — as the days 

 become longer. 



The product of the factories is starch. All the starch the world has 

 ever known has been made by plants. The greatest chemist wdio ever 

 lived could not make enough starch to stiffen his own shirt collar, yet 

 every summer tons and tons of it are made by the plants all about us. 



All the life in the world depends on starch. It is the foundation 

 food. When in the plant it is capable of going through a number of 

 changes, much as w^ater can change to vapor, steam, snow or ice, but to 

 a chemist, wdiatever the change of form may be, it is always water. The 

 starch grains which are made in the green parts of the plant can take on 

 changes and travel to all parts of its body and change back to starch 

 grains again and rest there until they are needed to enter the growth of 

 some of the many parts, such as new twigs, new roots, flowers or fruit 

 and particularly seeds. 



All thrifty trees — fruit trees we will say — will have more starch 

 than is needed for the time being and it is held for future use much as a 

 prudent man will put money into the savings bank for a time of need. 



If you wish to see with your own eyes the grains of starch which a 

 plant has stored away for future use, you can do so by using what is 

 called the iodine test. It is simple to make and your teacher may be kind 

 enough to help you in doing it. 



Into a small bottle put a few drops of tincture of iodine and add 

 fifteen times as much water as the quantity of the tincture. Keep the 

 bottle corked when not in use. On a thin slice of potato put a smrll 

 drop of diluted iodine, no more than will stick to the tip of a tooth pick 

 or broom splint. 



Instantly you will sec a purple stain. Under a lens, even of very lew 

 power, the stain shows as a collection of purple specks. Those are starch 

 grains which the iodine has colored. The starch grains in a potato are 

 important factors that make it so valuable as food. 



Not many weeks will pass by before you will be watching the willows 

 wdiich are among the first shrubs to awaken in the spring. Cut some 

 twigs and put them in a bottle of water. After a short time the buds will 

 enlarge and then the leaves will put out and a shoot will show a little 

 growth. 



All that growth requires sustenance, which comes from the starch 

 that was stored in the twig the season before. The water in the bottle 

 enables the starch to take a form so as to be available for making growth, 

 but water alone cannot give that growth. 



If hard times should come to ]ilantdom, all the trees and plants 

 having abundant stores of starch will live, while the half-starved trees 



