CONTENTS XV 



149. Conservation of Moisture Tilling . . . . 207 



150. Irrigation and Underdrainage ...... 210 



151. Soil Air 212 



Plant Food I 213 



Humus . . . .215 



Enriching the Soil . .216 



Green Manures . . . . . . . . . 217 



Barnyard Manure . . . . . . . .218 



Renovation of Worn-out Soils 220 



The Liming of the Soil ' . .220 



Commercial Fertilizers 222 



Use of Commercial Fertilizers 223 



Home-mixed Fertilizers 224 



Fertilizers for Garden Crops 225 



Plant Roots 226 



Plant Stems 227 



Leaves 228 



Buds . . 230 



Flowers . 231 



Fruits and Seeds . . . 232 



Flavoring Extracts and Perfumes 234 



Plant Food II 235 



171. The Propagation and Breeding of Plants . . . .236 



172. Plants Forestry 237 



173. Lower Forms of Plant Life Bacteria, Molds, and Mildew 238 



174. Fermentation Yeasts 240 



175. Alcohol for Purposes of Energy 241 



176. Lower Forms of Plant Life Fungi, Rusts, Mushrooms, 



etc. 243 



177. Protozoa and Amoebae 244 



178. Insects and the Smaller Animals . . ... . 245 



179. The Stings of Insects . . . * 246 



180. Animal Life Distribution 247 



The Invertebrates . .247 



Animal Life Fishes, Animals, and Birds . . . . 248 



Animal Life Man 249 



The Life Processes 250 



The Bones, or Framework 251 



The Lever and its Advantage 252 



