PAGE PREFACE vii FOREWORD ix CHAPTER I. THE HISTORY OF POISON GASES 1 II. MODERN DEVELOPMENT OF GAS WARFARE 10 III. DEVELOPMENT OF THE CHEMICAL WARFARE SERVICE 31 IV. THE CHEMICAL WARFARE SERVICE IN FRANCE 72 V. CHLORINE 116 VI. PHOSGENE 126 VII. LACHRYMATORS 137 VIII. CHLOROPICRIN 144 IX. DICHLOROETHYLSULFIDE (MUSTARD GAS) 150 X. ARSENIC DERIVATIVES 180 XI. CARBON MONOXIDE 190 XII. DEVELOPMENT OF THE GAS MASK 195 XIII. ABSORBENTS 237 XIV. TESTING ABSORBENTS AND GAS MASKS 259 XV. OTHER DEFENSIVE MEASURES 272 XVI. SCREENING SMOKES 285 XVII. TOXIC SMOKES 313 XVIII. SMOKE FILTERS 322 XIX. SIGNAL SMOKES 330 XX. INCENDIARY MATERIALS 336 XXI. THE PHARMACOLOGY OF WAR GASES 353 XXII. CHEMICAL WARFARE IN RELATION TO STRATEGY AND TACTICS 363 XXIII. THE OFFENSIVE USE OF GAS 385 XXIV. DEFENSE AGAINST GAS 405 XXV. PEACE TIME USES OF GAS 427 XXVI. THE FUTURE OF CHEMICAL WARFARE 435 INDEX 440 CHEMICAL WARFARE CHAPTER I THE HISTORY OF POISON GASES[1] The introduction of poison gases by the Germans at Ypres in April, 1915, marked a new era in modern warfare. The popular opinion is that this form of warfare was original with the Germans. Such, however, is not the case. Quoting from an article in the _Candid Quarterly Review_, =4=, 561, “All they can claim is the inhuman adoption of devices invented in England, and by England rejected as too horrible to be entertained even for use against an enemy.” But the use of poison gases is even of an earlier origin than this article claims. [Footnote 1: This chapter originally appeared in Science, Vol. =49=, pp. 412-417 (1919).]