CONTENTS. 



PART II. 



CHAPTER VI. 



PROTOPLASM AND ITS RELATIONS TO ITS SURROUNDINGS. 



PAGE 



Occurrence of Protoplasm 195 



Chemical and Physical Properties of Protoplasm 197 



Protoplasmic Movements 199 



Relations of Protoplasm to Heat 201 



To Light 206 



To Electricity 207 



To Mechanical Irritation 208 



To Gravitation 209 



To Moisture 209 



To Various Gases 210 



Structure of Protoplasm 211 



Continuity of Protoplasm 214 



Relations of the Cell-wall to Protoplasm 218 



Historical Note regarding Protoplasm 219 



CHAPTER VII. 



DIFFUSION, OSMOSIS, AND ABSORPTION OF LIQUIDS. 



DIFFUSION AND OSMOSIS 221 



Diffusion of Liquids , . . . 221 



Rate of Diffusion 222 



Osmosis 224 



Precipitation-membranes 225 



Traube's Cell 226 



Pfeffer's Apparatus for Osmosis 226 



ABSORPTION OF LIQUIDS THROUGH ROOTS 230 



Root-hairs 231 



Extent of Root-systems 232 



Adhesion of Soil to Roots 233 



Do Roots go in Search of Food ? 235 



CHAPTER VIII. 



SOILS, ASH CONSTITUENTS, AND WATER-CULTURE, 



Amount of Water and of Ash in Plants 236 



SOILS.' 237 



Formation of Soils 237 



