^^(i 



Rural School Leaflet. 



The best specimens found nia}- be preserved in the school room. 

 They will arouse interest on the part of patrons who visit the school. 



To preserve them, place the roots 

 in a wide mouth bottle or fruit jar, 

 and fill with 96 parts of water and 

 four parts of formalin. Then seal 

 tightly. If well sealed, they should 

 keep permanently. Do not forget to 

 label them. A few ounces of forma- 

 lin may be secured at a drug store. 

 Other materials may be preserved in 

 the same way. 



IV 



Bacteria are microscopic plants. 

 There are many kinds of them. One 

 kind causes typhoid fever and another 

 causes tuberculosis (consumption). 

 But the great majority are either 

 harmless or helpful to mankind. 



Certain kinds of these bacteria in 

 the soil are good friends to the farmer. 

 One kind lives on the roots of legumes 

 and causes the nodules or tubercles. 

 In some way these bacteria take nitro- 

 gen from the air so that it becomes 

 available for the growth of plants. 



The larger part of the air is nitro- 

 gen, but no plants can take nitrogen 

 from the air. They can onlv use it 

 when it is combined with other things. 

 The air between the particles of the 

 soil furnishes the nitrogen for the 

 bacteria on the legumes. These bac- 

 teria do not live on the roots of any 

 common plants except legumes. 



The reason why this is os impor- 

 tant a subject is because nitrogen is 

 the most expensive thing that farmers 

 buy in fertilizers. They now pay about 

 21 cents per pound for the amount 

 of actual nitrogen in a fertilizer. 

 Sometimes the bacteria are not in the soil, so that the legumes do 

 not have the tubercles. 



Fig. 16. — Nodules on the roots of red 

 clover. 



