xii CONTENTS 



PART V. RESPONSES IN PLANTS AND ANIMALS 



CHAPTER PAGE 



XVIII. How Body Control is Brought About. . . . 192 

 XIX. How Habits are Formed 208 



PART VI. REPRODUCTION AND CLASSIFICATION 



XX. Reproduction in Plants and Animals . . . .219 

 XXL Classification of Plants and Animals .... 234 



PART VII. MAN'S CONTROL OF HIS ENVIRONMENT IN 

 RELATION TO HEALTH 



XXII. Bacteria and Disease 253 



XXIII. How We Fight Bacterial Diseases .... 268 



XXIV. The Relations of Animals to Disease .... 278 

 XXV. Man's Improvement of his Environment . . . 292 



PART VIII. MAN'S CONTROL OF HIS ENVIRONMENT IN 

 RELATION TO WEALTH 



XXVI. Our Forests, their Uses and Need of Protection . 313 

 XXVII. The Value of Green Plants to Man . . . .323 

 XXVIII. Plants without Chlorophyll in their Relation to 



Man 334 



XXIX. The Economic Importance of Animals .... 347 

 XXX. Conservation and its Lessons 368 



PART IX. MAN'S CONTROL OF HIS ENVIRONMENT IN RE- 

 LATION TO EVIPROVEMENT OF PLANTS AND ANIMALS 



XXXI. Plant and Animal Breeding 380 



XXXII. The Improvement of the Human Race . . . 394 

 XXXIII. Some Great Names in Biology 405 



Glossary . . . • 415 



Weights, Measures, Laboratory Equipment . . 429 

 Index 431 



