CONTENTS. 7 



PACK 



CHAPTER V BIRDS. 



PURPOSES OF BIRDS IN THE CYCLE OF LIFE . . 130 



WHAT BIRDS FEED UPON . . . . . 131 



RELATION OF THE FOOD OF BIRDS TO FARMING 



AND GARDENING . . . . . . 134 



WHY BIRDS SHOULD BE PROTECTED . . 134 136-139 

 PLEASURE FROM THE BEAUTY AND THE CHEERFUL 



SONGS OF BIRDS . . . . . . 138 



INDIVIDUAL BIRDS THE USEFUL WOODPECKER . 139 

 WHY THE SWALLOW SHOULD BE PROTECTED . 141-143 

 THE MEADOW LARK, ITS FOOD, ITS CHEERFUL 



SONG ........ 144 



UNWISE DESTRUCTION OF QUAILS AND SPARROWS 147 

 THE OWL, THE HOUSE WREN, ROBINS BLUE- 

 BIRDS, BOBOLINKS . . . . 133, 148, 150 



CHAPTER VI BACTERIA. 



WHAT BACTERIA ARE . . . . . . 151 



THE THREE CLASSES USEFUL, HARMFUL, 



NEITHER USEFUL NOR HARMFUL . . . 151 



SHAPES OF BACTERIA, How THEY GROW . . 152 



CONDITIONS OF LIFE AND ACTIVE EXISTENCE . 154 

 How BACTERIA PRESERVE LIFE AND MAKE SOILS 



FERTILE 155 



WHY HEAT AND MOISTURE INJURE GRAIN AND 



HAY 158 



CAUSES OF DECAY IN FRUITS, VEGETABLES AND 



MEATS 158 



HOW FOOD MAY BE PRESERVED .... l6o 



SOURCES OF MILK CONTAMINATION . . . 161 

 BACTERIA BENEFICIAL IN BUTTER AND CHEESE- 

 MAKING 164 



How BACTERIA CHANGE CIDER TO VINEGAR . 165 



