Attention is also drawn to the solutions of mathematical problems in the different branches of hygiene, of which a table of contents is given on page viii. In its new form, it is hoped that this work will be found to have retained its value as a plain and straightforward account of its subject for the general public and for science students; and to have become a practical guide to sanitary inspectors and to medical students, whether preparing for a diploma in public health, or studying hygiene as an important branch of medicine. The use of smaller type for specially technical matter of less general interest will facilitate discriminative reading. ARTHUR NEWSHOLME. BRIGHTON, _February 28th, 1902_. TABLE OF CONTENTS. CHAPTER. PAGE I.—INTRODUCTORY 1 II.—FOOD 4 III.—THE VARIETIES OF FOOD 9 IV.—DISEASES DUE TO FOOD 23 V.—DIET 29 VI.—THE PREPARATION AND PRESERVATION OF FOOD 38 VII.—CONDIMENTS AND BEVERAGES 45 VIII.—FERMENTED DRINKS 55 IX.—WATER 65 X.—THE STORAGE AND DELIVERY OF WATER 74 XI.—IMPURITIES OF WATER 78 XII.—ORIGIN AND EFFECTS OF THE IMPURITIES OF WATER 89 XIII.—THE PURIFICATION OF WATER 94 XIV.—COMPOSITION AND PROPERTIES OF AIR 100 XV.—SUSPENDED IMPURITIES OF AIR 105 XVI.—GASEOUS AND OTHER IMPURITIES OF AIR 111 XVII.—TRADE NUISANCES 120 XVIII.—THE EXAMINATION OF AIR 125 XIX.—THE PURIFICATION OF AIR 129 XX.—GENERAL PRINCIPLES OF VENTILATION 132 XXI.—PROBLEMS AS TO VENTILATION 137 XXII.—METHODS OF VENTILATION 146 XXIII.—VENTILATION BY THE INTRODUCTION OF WARMED AIR 155 XXIV.—THE WARMING OF HOUSES 158 XXV.—HOUSE DRAINAGE 165 XXVI.—CESSPOOLS AND MAIN SEWERS 183 XXVII.—PROBLEMS AS TO FLOW IN SEWERS 187 XXVIII.—THE DISPOSAL OF SEWAGE 190 XXIX.—CONSERVANCY METHODS 194