CHAPTER VI. THE DAYS BEFORE YPRES 70 CHAPTER VII. THE SECOND BATTLE OF YPRES 83 CHAPTER VIII. THE AFTERMATH OF THE GAS 107 CHAPTER IX. THE MEDICAL ORGANIZATION OF THE BRITISH ARMY 125 CHAPTER X. KEEPING THE BRITISH SOLDIER FIT 134 CHAPTER XI. LABORATORY WORK IN THE FIELD 152 CHAPTER XII. SKETCHES FROM A LABORATORY WINDOW 169 CHAPTER XIII. PARIS IN WAR TIME 189 CHAPTER XIV. TABLE TALK AT A FLANDERS MESS 211 CHAPTER XV. ON THE BELGIAN BORDER 230 LIST OF ILLUSTRATIONS Colonel George G. Nasmith, C.M.G. Frontispiece Mechanical Transports in Salisbury Floods 16 Major-General M.S. Mercer, C.B. 64 German Barrage Fire at Night 104 French Soldiers Advancing under Cover of Liquid Fire 176 The Camouflage 208 "Home, Sweet Home"--Mud Terrace 232 British Tanks as Used in the Flanders Offensive 248 PREFACE On April 22nd, 1915, the writer, in company with Major Rankin, saw the Germans launch their first gas attack near St. Julien upon the section of the line held by the French colonial troops and the first Canadian division. This book was written primarily for the purpose of recording this as well as some of the other experiences of the first Canadian division as seen from the unusual angle of a scientist, in the course of 18,000 miles of travel in the front line area. It had the secondary object of giving the average reader some insight into what goes on behind the lines, and the means employed to maintain the health and efficiency of the British and Canadian soldiers in the field. No attempt has been made to deal with the work of the real fighting men on land and in the air; others far better qualified than I are doing that. If the book has no other merit, it has, at least, that of being literally true. ON THE FRINGE OF THE GREAT FIGHT CHAPTER I. ON THE ROAD TO A GREAT ADVENTURE.