84 AGRICULTURE ON THE PACIFIC SLOPE 



Test for proteins as follows: On a piece of boiled 

 white of egg put a drop of nitric acid and then a few 

 drops of ammonia water. The yellow color is a test 

 for protein. Try the test on soaked seeds (especially 

 peanut, beans, Brazil nut). Be careful in handling 

 the acid; it burns skin and clothing. 



What happens if some of the food is taken away 

 from the seed? Remove the skin from some well- 

 soaked beans and place them on moist sand or blotting 

 paper, first taking one or both seed leaves from some of 

 them. The dish in which they are placed may be cov- 

 ered with a piece of glass to keep the air moist. 



All these foods in the seed are used by the growing 

 plant or by animals which eat the seeds. 



In what way is food used ? The food is either (1) 

 burned up, (2) built up into the plant, or (3) stored up. 

 Much food is burned up. We must think of the plant 

 as a machine which needs energy or power to run it. 

 An engine gets its power from the coal or wood it 

 burns, and the plant gets its energy from the food it 

 burns. We all know that in cold weather we have to 

 eat more to keep up the heat of our bodies, because we 

 then burn up more food. Some small plants (bacteria) 

 burn up more than their own weight of food every day. 

 Figure 44 shows a frog, a burning candle, and some 

 sprouting seeds placed in separate closed bottles or 

 jars. After a time the air in all three jars is found to 

 be changed so that nothing will burn in it. But if we 



