CHAPTER I. PAGE THE PLANT AND ITS SURROUNDINGS, 1 CHAPTER II. THE PLANT AND ITS FOOD, 7 CHAPTER III. THE PLANT A LIVING MACHINE, 15 CHAPTER IV. METABOLISM, 23 CHAPTER V. ROOTS AND ROOT-HAIRS, 35 CHAPTER VI. THE FUNCTIONS OF ROOT-HAIRS, 45 CHAPTER VII. THE BIOLOGY OF SOIL, 56 CHAPTER VIII. HYBRIDISATION AND SELECTION, 69 _PART II.--DISEASE IN PLANTS._ CHAPTER IX. PHYTOPATHOLOGY. DERIVATION AND MEANING, 85 CHAPTER X. HEALTH AND DISEASE, 91 CHAPTER XI. CAUSES OF DISEASE, 99 CHAPTER XII. CAUSES OF DISEASE. THE LIVING ENVIRONMENT, 108 CHAPTER XIII. NATURE OF DISEASE, 119 CHAPTER XIV. NATURE OF DISEASE (_Continued_), 130 CHAPTER XV. SPREADING OF DISEASE AND EPIDEMICS, 142 CHAPTER XVI. THE FACTORS OF AN EPIDEMIC, 149 CHAPTER XVII. REMEDIAL MEASURES, 159 CHAPTER XVIII. VARIATION AND DISEASE, 168 CHAPTER XIX. SYMPTOMS OF DISEASE, 179 CHAPTER XX. SYMPTOMS OF DISEASE (_Continued_), 186 CHAPTER XXI. ARTIFICIAL WOUNDS, 194 CHAPTER XXII. NATURAL WOUNDS, 204 CHAPTER XXIII. EXCRESCENCES, 212 CHAPTER XXIV. EXCRESCENCES (_Continued_), 222 CHAPTER XXV. EXUDATIONS AND ROTTING, 227 CHAPTER XXVI. NECROTIC DISEASES, 240 CHAPTER XXVII. MONSTROSITIES AND MALFORMATIONS, 246 CHAPTER XXVIII. PROLIFERATIONS, 257 CHAPTER XXIX. GRAFTS, 262 CHAPTER XXX. LIFE AND DEATH, 271 INDEX, 293 _PART I._ SOME FACTORS. CHAPTER I. THE PLANT AND ITS SURROUNDINGS. _The plant the central object of study--soil, climate, atmosphere, etc., are factors of its environment. Agricultural chemistry. The plant a machine. Physiology._