The second includes those _with lung involvement_ and associated with physical chest signs, in some indefinite and confusing, while in others definitely conforming with the existing pathology. These symptoms and chest signs were those associated at one time with what appeared to be an acute œdema of the lungs. At another time the physical signs were those of a bronchiolitis (capillary bronchitis), or most frequently of a broncho-pneumonia, of an isolated type or of a massive type. Finally there were some forms of lobar pneumonia which at times we were unable to differentiate from a true lobar (croupous) pneumococcic pneumonia. _Influenza Without Lung Involvement_ Of the group without lung involvement nothing further would seem necessary to be said in addition to what one finds in standard text-books describing the disease picture of former epidemics. The incidence of influenza of this type among our group was as follows: Of 153 soldiers 93, or about 60 per cent., had a so-called simple, uncomplicated influenza, and of the 394 civilians 185, or about 52 per cent., had no lung involvement. There are a few points in which the symptoms of the present epidemic seem to be so peculiar that they merit special consideration. _The Temperature_ This can be described as showing a sudden rise to 102–104, at which point it is maintained for a few days, and subsides by lysis in a few days more. A typical chart is as follows: [Illustration: CHART I ] Or the temperature might fall one or two degrees for a day or so after the first rise, and then go up again for one or two more days, and subside by lysis as is shown in Chart II. [Illustration: CHART II ] This would occur without our being able to find any lung lesion unless we accept the acute œdema or wet lung as a complication, and this we were rarely able to recognize by any definite physical signs in the chest. Cyanosis frequently accompanied this second rise of temperature, and was later interpreted as being associated with the so-called wet lung. When the temperature remained up longer than five days it could safely be concluded that lung involvement must be present. _The Pulse and Respirations_