In influenza-pneumonia, on the other hand, the events taking place in a given lobe are not uniform and various stages and grades of the inflammatory reaction may be recognized at the same time, some appearing red, some congested, some flooded with blood in hemorrhage and others showing the purulent infiltration by the appearance of gray patches upon the background of red. Not only do the various reactions within the same lobe fail to show similar grades of intensity and similar stages or time of involvement, but we find that all of the red and hemorrhagic areas are not destined to pass through the gray stages. At times it is true an entire lung will enter into the purulent phase and if this becomes extreme abscess and gangrene are almost certain to develop. But often the purulent infiltration occupies only a few or scattered lobules and resolution may take place in a lung where the greater part of the lobes is occupied by the inflammatory œdema and hemorrhage and has never become truly consolidated by cellular and fibrinous exudate. This feature that the involved lung tissues need not pass through the sequence of events which is usually observed in frank lobar pneumonia is so distinctive that it differentiates the character of the inflammatory reaction very clearly. It may be that this is an indication of the unequal distribution of the micro-organism and that the first infection presumably by the _bacillus influenzæ_ has been much more diffuse and of wider extent than the secondary invading bacteria which being distributed through the bronchial tree are more or less localized to those lobules most severely involved. It is impossible to claim for influenza-pneumonia as clear and sharp-cut stages as we obtain them in the pneumococcus lobar pneumonia. During the period of the intense purulent reaction in certain portions of the lung, the intrinsic structures within the area also partake in the damage and response. The suppurative infiltration not only occupies the alveolar walls but also extends through the tissues of the bronchioles, the arteries and the veins. The polymorphonuclear leucocytes seem to migrate into all of the parenchyma indicating some damage by bacterial invasion. On more than one occasion have we observed partial or incomplete thrombosis of arterioles and capillaries whose walls showed an acute suppurative reaction. Some of these thromboses are of importance, being associated with the interference with a blood supply not compensated by adequate anastomosis. Necrosis and small areas of gangrene and abscess are to be found in the region of the circulatory disturbances. It is also during this period of the disease when the bronchi and their ramifications contain pus or muco-pus, that the exudate from the alveoli readily finds its way into the air passages and becoming mixed with the mucus from these tracts forms a tenacious discharge.