Vlll 



Contents 



CHAPTER 



XXV. Respiration 339 



XXVI. Food Values 354 



XXVII. Food and Its Preparation . . . 369 



XXVIII. Stimulants 377 



XXIX. Narcotics 382 



XXX. How Alcohol Affects Cell Life 392 



XXXI. How Our Bodies Digest and Absorb Food 398 



XXXII. Digestion and Health 409 



XXXIII. Circulation, Assimilation, and Excretion 416 



XXXIV. Our Nervous System and How It Works 430 



XXXV. Bacteria, Helpful and Otherwise 439 



XXXVI. Protection Against Disease 451 



XXXVII. How to Keep Well 465 



XXXVIII. First Aid 478 



General Thought Questions for Discussion and Review 487 



XXXIX. The Green Plant 491 



XL. Seeds and How They Grow 504 



XLI. Forests and What They Give Us 514 



XLII. Plants, Helpful and Harmful 527 



XLIII. Our Balanced World 535 



XLIV. Science and Progress 546 



XLV. Famous Scientists 555 



XLVI. New Developments in Science 580 



General Thought Questions for Discussion and Review 612 



Glossary 614 



Index . 647 



