=Blood-vessels.=--A similar difference of opinion obtains in regard to the changes in the walls of the blood-vessels, especially of those in hemorrhagic areas. This question is of particular interest because of its bearing on the problem of the mechanism involved in the escape of the blood. Since it has been demonstrated that neither the clotting time nor the viscosity of the blood is markedly changed in scurvy but that weakness of the vessel walls exists, as demonstrated by "the capillary resistance test," it is natural that we should seek an explanation in the microscopic pathology of the vessels. So far no change has been found. The application of some of the newer stains, such as those for mitochondria and other cell granules, has not been resorted to for this study, and might furnish valuable information. Hayem found fatty infiltration of the walls of the small veins and capillaries, and believed this to play an important rôle in the etiology of these bleedings. Lasèque and Legroux also found occasional fatty changes. Other authors have failed to demonstrate similar lesions, or have considered them due to postmortem change. Koch searched in vain for "rents" in the vessel walls to account for the escape of blood. Hyaline degeneration has also been described, but is believed to result from secondary infections and not to be an intrinsic lesion of scurvy (Sato and Nambu, Aschoff and Koch). Thrombosis of vessels is found both in the neighborhood of hemorrhage and elsewhere, the thrombi at times completely occluding the vessels and giving rise to typical wedge-shaped infarcts. The lung often shows areas of this kind. =Lungs.=--Hemorrhages of various size occur in the tissue of the lung or in the air spaces. Hemorrhagic infarcts also have been described, and Sato and Nambu report hyaline degeneration of the blood-vessel walls. Secondary pneumonias, usually broncho-pneumonic in type, are of common occurrence, and in many epidemics constitute the prevailing cause of death. Tuberculous lesions are also frequently present, and are stated to assume fresh activity as the result of the nutritional disorder. Edema occurs frequently, the fluid in the acini often containing red blood-cells. Subpleural hemorrhages, thickening of the pleura, purulent or fibrinous pleurisy are common lesions. =Heart.=--Although hypertrophy and dilatation of the heart have been noted by several observers, microscopic changes have rarely been recorded. Meyer, and also Leven, report fatty degeneration of the muscle fibres, which, however, was found by Aschoff and Koch in only one case. Sato and Nambu described an increase of connective tissue, and others anemia and pigmentation. Thickening of the pericardium and subserous hemorrhages also occur. ALIMENTARY TRACT