CONTENTS 



CHAPTER PAGE 



I. The General Problem — Some Reasons for the Study 



OF Biology ......... 1 



PART I. LIVING THINGS IN RELATION TO THEIR 

 ENVIRONMENT AND TO EACH OTHER 



11. The Environment of Plants and Animals ... 7 

 HI. Living Things and the Environment .... 13 

 IV. The Interrelations of Plants and Animals . . 24 



PART II. LIFE PROCESSES IN LIVING THINGS. 

 GREEN PLANTS AS LIVING ORGANISMS 



V. The Building Material of Living Things ... 43 



VI. Plant Growth and Nutrition. Causes of Growth . 51 

 VII. Organs of Nutrition. Roots in Relation to the 



Soil 63 



VIII. How Green Plants Make Food 75 



IX. The Circulation and Final Uses of Food by Plants 87 



PART HI. GENERAL RELATIONS BETWEEN PLANTS AND 



ANIMALS 



X. The Simplest Organisms 95 



XI. The Relations of Plants to Animals .... 102 



PART IV. ANIMALS AS LIVING ORGANISMS 



XII. Animal Organisms. The Human Machine . . . 107 



XIII. A Study of Foods and Dietaries 118 



XIV. Dangers from Food Adulteration, Alcohol, and 



Drugs 138 



XV. How Food is Prepared for Body Uses . . . 146 



XVI. The Blood and its Circulation 162 



XVII. Respiration and Excretion 177 



