The term _hæmoptysis_ (αιμα, blood, πτυω, I spit,) is now entirely restricted to bleeding from the lungs and lower air passages. It is a very rare complaint in the lower animals, but is sometimes seen in both horse and ox. In very plethoric subjects the overloaded circulatory organs give way in the delicate membrane, lining the ultimate bronchial tubes and the air cells. The exciting cause in such cases is usually some severe effort of draught, a violent gallop, or other unwonted exertion. It occurs in glanders from rupture of caseated pulmonary nodules. It does not appear to be so common in phthisis in the lower animals as in man, but one case occurred under the eye of the writer in which the bursting of a large tubercle in the lung of a cow involved the rupture of a considerable vessel with a fatal result. Pulmonary embolism and infarction, petechial fever, aneurism, ulcerated neoplasms, anthrax, and septicæmia are additional causes. Lastly hæmoptysis sometimes takes place in hæmorrhagic subjects without any appreciable rupture of vessels, the blood sweating from the surface of the bronchial mucous membrane. Premonitory symptoms are sometimes noticed, such as dulness, and lassitude, loss of appetite, a frequent short cough, coldness of the limbs and surface, shivering, full, hard pulse, pulsation in the jugulars, tumultuous action of the heart, and unsteadiness of gait. More commonly it comes on suddenly as the result of severe muscular strain or excitement. The blood flows from the nose, and rarely from the mouth in solipedes, but indiscriminately from both in other animals. It is bright red, clear, frothy, or mixed with mucus, and variable in amount. It is easily distinguished from nasal hæmorrhage, which is not frothy, and from bleeding from the stomach, which is clotted and blackened, with an acid odor from the presence of the gastric juice. The cough of hæmoptysis contrasts with the sneezing of epistaxis and the retching of hæmatemsis. The rattling cough increases the discharge, as does also a dependent position of the head. Besides the cough there is usually an anxious countenance, accelerated breathing and considerable lifting of the flank. When the loss is excessive there is weakness, giddiness, rolling of the eyes, and pallor of the visible mucous membranes. The previous ill-health of the patient, the presence of tubercle as ascertained by auscultation and percussion, and the hæmorrhagic constitution as shown by occurrence of bleeding from other parts of the system will lessen the chances of a favorable termination. Sometimes, too, the flow is so profuse that the blood cannot be coughed up, and filling the bronchial tubes it destroys life suddenly by suffocation.