CONTENTS. 



Page. 



General Remarks on the Mineral Constituents Found in Organisms. 5 



Historical notes 5 



Ecological and jihysiological role of mineral substances 8 



Mineral compounds found in organisms 9 



General value of certain mineral salts 9 



The low atomic weight of the mineral nutrients 11 



The Ph\ siological R6le of Phosphoric Acid 11 



Relation of phosphoric acid to proteids and to the division of cells 11 



The physiological importance of lecithin 12 



Phosphoric acid in chlorophyll 14 



Potassium phosphate as a cell constituent 14 



The Ph^ siological R.6le of Iron Compounds 15 



Relation between the coloring matter of the blood and of the leaf 15 



Influence of iron and other mineral nutrients on the formation of chloro- 

 phyll 15 



Fertilizing effect of iron salts ' 16 



Organic compounds containing iron 17 



Iron in fungi 17 



Manganese in plants 17 



The Physiological R6lb of Halogen Compounds 18 



Plants raised without chlorids 18 



Valne of potassium chlorid for buckwheat 18 



Injurious effects of chlorids on plants 19 



Absorption of chlorids by aquatic plants 19 



Sodium chlorid in animals 20 



Physiological occurrence of calcium fluorid 20 



Behavior of plants to potassium bromid 20 



Relations of organisms to iodine compounds 20 



The Physiological Role of Alkali Salts 21 



Importance of potassium for the formation of starch and protein 21 



Beneficial action of sodium salts 23 



Can potassium salts be replaced by rubidium salts in green plants and in 



animals? 23 



Necessity of sodium salts for animals 25 



Behavior of fungi toward rubidium salts 25 



Physiological superiority of potassium salts . ., 26 



The Physiological Role of Calcium and Magnesium Salts 28 



Distribution of lime and magnesia in plants 28 



The physiological importance of lime salts in plants 30 



Views on the functions of lime salts 33 



Formation of lime incrustations 38 



Can calcium in plant cells be replaced by strontium? 39 



Poisonous action of magnesium salts 42 



3 



