THE PLANT AND THE SOIL 45 



PRACTICAL EXERCISES 



1. Lay a moistened piece of cloth or blotter upon a plate and 

 place several seeds of radish or some other plant. Cover with 

 another plate. In a few days look for the delicate root hairs on 

 the roots of the germinating plants. All the food materials 

 that plants take from the soil are absorbed by the root hairs. 



2. Place a few grains of corn on a marble slab, and cover them 

 with soil to a depth of one or two inches. After two weeks of 

 growth remove the plants, and wash the marble to see how the 

 roots have dissolved a little of the marble by the action of 

 carbon dioxide which is excreted from the roots. 



REFERENCE 



Farmers' Bulletins: 408, School exercises in plant produc- 

 tion. 



