There are several other points of resemblance between horse influenza and human influenza. The mortality from influenza among horses is under ordinary circumstances between two and seven per cent., and is highest in horses worn out by fatigue after a long railroad journey, among fat horses out of condition, and among horses which have been driven after they were sick. The death rate in the simple catarrhal form of influenza rarely exceeds one-half of one per cent., while in the pectoral form it is never less than four or five per cent., and may reach 16 per cent. The only measure of prevention which has been found wholly satisfactory is strict isolation. Usually influenza occurs in horses who have newly arrived in a stable from elsewhere. Practically all the newly arrived horses and country horses are almost alone susceptible. Soper, who has studied the records, such as they are, in the army veterinary corps, and also the records from the Bureau of Animal Industry, concludes that they show nothing to indicate that any general epizootic of influenza occurred among horses during the year 1918 corresponding to, or connectable with the pandemic of influenza among human beings. There was influenza among the horses, but he does not think it was extensive enough to be allied with influenza among human beings. He concludes that there are two types of influenza among horses, first a mild form which nearly all horses get when transferred to a contaminated stable, after which there develops immunity, and the second type, a true epizootic which may sweep the entire country, attacking practically every horse. A most suggestive result of his study lies in the fact that predisposing influences play a most important part in the production of serious influenza among horses. Aside from noting a certain similarity between the epizootic of so-called influenza in horses and influenza as we know it in man, we cannot acquire much additional information concerning influenza itself from a consideration of this subject. The important conclusion is that in several of the most important epidemiologic features the two diseases are similar and that the study of human influenza may be furthered by critical studies of influenza in horses. We shall attempt to demonstrate that influenza in a similar manner is not unlike other epidemic diseases. _Asiatic cholera._—There are those who claim that the disease should be compared with Asiatic cholera which remains constantly endemic on the banks of the Ganges and at intervals spreads from there throughout Indo-China, and formerly at times throughout the civilized world. Those who compare influenza with this disease believe that this is additional evidence in favor of a single focus of endemicity of influenza.