Читать книгу The Body at Work: A Treatise on the Principles of Physiology онлайн

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When the circulation is sluggish, owing to the inefficiency of the heart, the tissues become œdematous. In other words, lymph accumulates in the tissue-spaces. When the skin of a healthy person is pressed, it returns to its natural position as soon as the pressure is removed. If there is a tendency to dropsy—for ages the term “hydropsia” has been thus familiarly clipped—the finger leaves a pit behind it when pressed upon the skin. It is some little time before the lymph in the connective-tissue sponge readjusts the surface. Excessive escape of lymph from the blood, or its insufficient return into the blood, may also be the result of obstruction to the flow in the great veins. When the veins of the leg are varicose, the weight of the column of blood in the distended vessels impedes its circulation. After standing, the tissues about the ankle become œdematous. The œdema disappears on lying down. A hardening (cirrhosis) of the liver impedes the circulation of the blood which comes to it through the portal vein from the walls of the alimentary canal. The capillaries of the stomach and intestine are distended. Lymph accumulates in the abdominal cavity, producing ascites, another form of dropsy.