x CONTENTS . 



PAGE 



CHAPTER XLI. EXCRETION 403 



Source of waste. Organs of excretion. Kidneys, Lungs, Skin. Heat 

 regulation. 



CHAPTER XLII. THE NERVOUS SYSTEM 408 



Location and functions of cerebrum, cerebellum, medulla, . spinal 

 cord, sympathetic system. Regions of control for various activities. 



CHAPTER XLIII. THE SENSE ORGANS 415 



Irritability. Touch. Taste. Smell. Hearing, structure of ear, 

 care of ears. Sight, structure of eye, care of eyes. 



CHAPTER XLIV. BIOLOGY ,AND HEALTH 425 



Hygiene of Muscles, of Digestion, Breathing. Bathing. Care of 

 eyes, teeth, feet. Posture. Sleep. 



CHAPTER XLV. Civic BIOLOGY 440 



Food control. Sanitation. Disease prevention. Housing conditions. 

 Food laws. Medicines. 



CHAPTER XL VI. ECONOMIC BIOLOGY OF PLANTS 446 



General uses. Harmful forms. Plant uses in detail. 



CHAPTER XLVII. ECONOMIC BIOLOGY OF INVERTEBRATES 467 



General uses of animals. Harmful forms. Importance of each 

 group in detail. Harmful insects and their treatment. 



CHAPTER XL VIII. ECONOMIC BIOLOGY OF VERTEBRATES 480 



Fish. Amphibia. Reptiles. Birds. Mammals. 

 CHAPTER XLIX. BIOLOGY AND AGRICULTURE 486 



Soil formation. Plant breeding and protection. Animal husbandry. 



Bacteria on the farm. 

 CHAPTER L. ECONOMIC IMPORTANCE OF FORESTS 495 



Value of forests. Enemies of forests. Protection. Timber structure. 



Street trees. 

 CHAPTER LI. TOBACCO AND TABLE BEVERAGES . 508 



Tobacco, physical and social objections to its use. Tea, Coffee, 



Cocoa, and Chocolate. 

 CHAPTER LII. ALCOHOL IN RELATION TO BIOLOGY . . 514 



Composition and kinds of alcoholic liquors. Physical effects. Not 



a food. Alcohol and disease. Waste of resources. 

 CHAPTER LIII. SOME GENERAL BIOLOGIC PROCESSES . . 524 



Osmosis in life processes. Oxidation. Circles in Nature. Evolution 



of life functions. 

 CHAPTER LIV. HISTORICAL DEVELOPMENT OF BIOLOGY . . 



Biologic development. The work of Pasteur, Roux, von Behring, 



Lister, Carrell, Flexner. Darwin, Huxley, Mendel, Burbank. 



INDEX.. 549 



