Besides the affections of the lungs which impede respiration (as pneumonia, hydrothorax, etc.), we may have dyspnoea induced by extra-pulmonary causes, such as dilatation of the heart, aneurism of the aorta, mediastinal cancer, pleuritic effusion; also by abdominal dropsy, extreme elephantiasis, etc. Mention need hardly be made here of respiratory obstruction from defective or injurious qualities of the air, threatening or producing asphyxia. Sighing respiration takes place in heart disease not infrequently. A peculiar modification of the breathing movements has been associated especially with fatty degeneration of the heart. From the distinguished authors who first described it this is called the Cheyne-Stokes respiration. Intervals of suspension of breathing occur, after which short, shallow inspirations begin, and gradually increase for a time in depth; then they grow shorter and shallower again, until apnoea is reached. Such a cycle may occupy from half a minute to a minute and a half, with from fifteen to thirty increasing and decreasing respirations in all. It has been shown by several observers that this type of respiration is not peculiar to fatty degeneration of the heart. It has been met with in cases of cardiac dilatation, aortic atheroma, cerebral hemorrhage, tubercular meningitis, and uræmia. Sometimes a kind of dyspnoea common in advanced disease of the heart, especially in mitral lesion with dilatation, has been confounded with this. Here the breathing is constantly labored (orthopnoea); but the patient from time to time dozes off into an imperfect sleep, in which the breathing almost entirely ceases. Then he is awakened with a start of distress, perhaps out of a painful dream. This succession of dozing apnoea and waking dyspnoea belongs to a late stage of heart disease, and usually ends in death. Stertorous respiration is familiar in apoplectic coma, as well as in that of brain compression from injury or from opium or alcoholic narcotism. In uræmic coma true stertor is less apt to be observed; sometimes the respiration in this condition has a hissing sound. Along with the movements of respiration we may notice that the breath {158} is hot and has a heavy odor in the early stages of all febrile disorders. Disagreeable breath is common, however, in persons not ill, from bad teeth or from indigestion. It is worst of all, putrid, in gangrene of the lung. Certain cases of chronic or subacute bronchitis (as well as of ozæna) also have very offensive breath. Coldness of the breath is a very bad sign; it is observed sometimes before death in the collapse of cholera. Hiccough (singultus) is a spasmodic affection of the diaphragm. It is innocent, though annoying, in most cases, resulting from indigestion or from nervous disorder; in children, occasionally, from long crying. When it takes place in cases of general prostration it betokens threatening depression or exhaustion of vital energy.