X TABLE OF CONTENTS 



PART IV 

 THE BIOLOGY OF MAN 



UNIT X. HOW DOES THE HUMAN MACHINE DO ITS 



WORK? 



Problem page 



I. What Is the General Structure of the Human Body? 314 



II. What Is the Structure of the Skin? 316 



III. What Is the Relation of Muscles to Bones? . . . 318 



UNIT XL HOW DOES MAN DETERMINE THE 

 VALUES OF FOODS? 



I. What Do Foods Do for Us? 327 



II. What Do Vitamins Do for Us? 333 



III. What Is the Relation of Work, Environment, Age, 



Sex, and Digestibility of Foods to Diet? . . . 335 



IV. What Is the Best Proportion of Nutrients for Our 



Daily Diet? 340 



V. What Is the Daily Calorie Requirement? . . . 343 

 VI. How Can the Relative Cheapness of Foods Be Deter- 

 mined? 345 



VII. What Is Adulteration? 348 



VIII. What Is the Truth about Stimulants and Narcotics? . 350 



IX. How Does the Pure Food and Drugs Act Work? . . 355 



UNIT XII. HOW IS FOOD PREPARED FOR BODY USES? 



I. What Is a Gland and How Does It Do Its Work? . . 361 



II. What Is the Structure and Work of the Mouth Cavity? 363 



III. What Are the Parts of the Digestive Tract? . . . 367 



IV. What Digestive Changes Take Place in the Stomach? . 369 

 V. What Work Is Done by the Pancreas? .... 373 



VI. What Are the Functions of the Liver? .... 375 

 VII. How Are Foods Absorbed and How Do They Get into 



the Blood? 376 



UNIT XIII. HOW ARE FOODS CIRCULATED AND 

 USED IN THE BODY? 



I. What Is the Composition and What Are the Uses of 



Different Parts of the Blood? 386 



II. What Are the Functions of Some of the Endocrine 



Glands? . . . .392 



III. How Does the Blood Circulate through the Body? . 395 



IV. What Is Respiration? 403 



V. What Are the Mechanics of Breathing? .... 406 



