The history of influenza can justly be divided into two phases, the first ancient, and the second modern. The latter period begins with the 1889 pandemic. By that time the science of bacteriology had altered our concepts of the etiology of disease and epidemiologists had begun to avail themselves of statistical methods of analysis. For the purposes of this paper, therefore, consideration will be given chiefly to the epidemic of 1889, and a summary of earlier epidemics will be made merely to refresh our minds concerning the antiquity of the disease and the periods of its occurrence. References to the earlier epidemics will be made more particularly in the special discussions later, where points of similarity or difference will be brought out. Further than that it is unnecessary to go in the history of the disease, for the several excellent monographs of 1890 to 1900 tell the historical story in a manner that could scarcely be improved upon. The great antiquity of epidemic influenza is a fact which I think may be admitted in spite of some who hesitate to accept it because of lack of convincing descriptive evidence. Some believe that the epidemic of the year 412 B.C., described by Hippocrates and by Livy, was an epidemic of influenza. Some have suggested that the epidemic described by Thucydides was the same disease. Parkes remarks that the epidemic pervading the Athenian Army in Sicily in 415 B.C., recorded by Diodorus Siculus, has been supposed to have been influenza. Finkler, in referring to a report by Diodorus of a pestilence occurring in 395 B.C., which broke out in the Greek Army at the siege of Syracuse, and which killed off the soldiers murderously, says that this could not have been influenza. He regards as sufficient argument the fact that the mortality was high. After the epidemic of 1918, one is more inclined to believe that the epidemic in Sicily may well have been true influenza. We must remember that previous to the last few pandemics the stories have been fragmentary in character and were told, not by physicians, but chiefly by the historians of the time, men who have desired to impress their readers with some idea of the horrible ravages of the disease, and who have doubtless in some instances transmitted the impression of monstrous mortality rates. The early historians were much given to figures of speech, many of which were very telling in conveying the impression desired. Finally, the writers of the middle ages and of earlier times had little or no statistical material on which to base their conclusions. I have no doubt that a historian who during the 1918 epidemic of influenza might have limited his observations entirely to the disease as it occurred at Camp Sherman, Ohio, and who saw 125 robust soldiers dying each day, would have truly written that the disease killed off the soldiers murderously. A further statistical argument in favor of considering the epidemic among the Greek soldiers as quite