viii ELEMENTARY BIOLOGY 



CHAPTER PAGE 



XXV. Stimulants, Narcotics, and Poisons 131 



XXVL Alcohol and Health 133 



XXVII. Alcohol and Society 137 



XXVIII. Air and Life 143 



XXIX. Breathing in Man 148 



XXX. Ventilation 154 



XXXI. Contaminated Air 158 



XXXII. First Aid and Hygiene in Relation to Breathing 169 



XXXIII. Transfer of Materials in Plants 174 



XXXIV. The Blood 1 79 



XXXV. The Circulation of the Blood 185 



XXXVI. Hygiene of the Circulatory System .... 190 



XXXVII. The Blood as a Living Tissue 193 



XXXVIII. Wastes and By-products of Organisms .... 201 



XXXIX. Hygiene of Excretion 205 



XL. Excretion and Fatigue 208 



XLI. Fatigue and the Worker 213 



XLII. Nerves and the Reactions of Organisms. . . 217 



XLIII. Tropisms and the Beginnings of Sense . . . 224 



XLIV. Eyes and Light 229 



XLV. Hygiene of the Eyes 235 



XLVI. Sound Sensations 238 



XLVII. Responses to Gravity 241 



XLVIII. Instincts 244 



XLIX. Habit . 248 



L. Chemical Injury to the Nervous System . . . 253 



LI. Unity of Life 260 



PART III. THE CONTINUITY OF LIFE 



LII. Growth and Regeneration 265 



LHI. Development 274 



LIV. Conditions for Development 285 



LV, New Orc;anisms 291 



