CONTENTS 



CliAFTFR PAOR 



I. Some Reasons for the Study of Biology . . .13 



'"11. The SuiiROUNDiNGS ou Environment of IjIVing Things 1 i. 



y — III. The Functions and Composition ok Living Things 26 



IV. Flowers and their AVork . .... 34 



V. Fruits and their Uses 51 



VI. Seeds and Seedlings ....... 6^ 



VII. Roots and their Work 84 



VIII. The Structure and Work of the Stem ... 98 



IX. Leaves and their Work 115 



""S X. Our Forests; their Uses and thk. Necessity for 



their Protection . . .... 133 



XI. The Vari<.)US Forms of Plants and how they Repro- 

 duce Themselves ....... 144 



XII. How Plants are modified by their Surroundings . 159 



XIII. How Plants benefit and iiAii:\i ^Iankind . . . 170 



"^XIV. The Relations of Plants to Animals . . . 184 



XV. The Protozoa 190 



XVI. The Mbtazoa. — Division of Labor .... 199 

 XVH. The Wor.ms, a Study oi- Relations to Environ- 

 ment '212 



XVIII. The C'rayfish. A Study of Adaptations . . . 221 



XIX. The Insects 233 



XX. General Considerations from the Study of Insects 249 



XXI. The Mollusks L'liT 



11 



