I. The Pathology of the Respiratory Tract in Influenza 13 (A) Lesions of the Trachea and Bronchi 13 (a) Gross Picture 13 (b) Histological Picture 14 (c) Summary 16 (B) Lesions of the Lung 16 (1) Acute Diffuse Fulminating Type 18 (a) Gross Picture 18 (b) Summary 19 (c) Histological Picture 20 (d) Summary 22 (2) Localization and Necrotization of the Pneumonic Process 22 (a) Gross Picture 22 (b) Histological Picture 24 (c) Summary 26 (3) Organization of the Bronchiolar and Pneumonic Processes 26 (a) Illustrative Protocols 27 (b) Summary 30 II. Influence of the Respiratory Complications of Influenza upon Tuberculosis of the Lung 32 (a) Illustrative Protocols 32 (b) Summary 33 III. Extrarespiratory Lesions in Influenza 34 (A) Lesions of the Hematopoietic System 34 (a) Lymphadenoid Tissue 34 (b) Spleen 35 (c) Bone Marrow 35 (B) Lesions of the Blood Vessels and Elsewhere in the Body 36 (a) Vascular System 36 (b) Skeletal System 36 (c) Parenchymatous Organs 36 (d) Alimentary Canal 37 (e) Urinary Bladder 37 (C) Miscellaneous Lesions 38