Haemorrhage , (Gr. Haemorrhage 0800255 blood, and Haemorrhage 0800256 obs. Haemorrhage 0800257 to burst), an escape of blood from the vessels of the living body, called active or passive according as it is arterial or venous in character. Haemorrhage may be natural, as in the menstrual discharge; symptomatic of disease, as in scurvy, typhoid fever, epistaxis, and haemorrhoids; essential, inasmuch as the bleeding appears to constitute the principal disease, arising from and keeping up a degeneration of the vital fluid; and traumatic, when the blood vessels are wounded. Active haemorrhage, when not traumatic, consists in an escape of blood from the capillaries, distended and ruptured by inflammation and excitement, as in bleeding from the mucous membrane of the lungs, nose, rectum, urethra, and from granulating wounds; this is accompanied by local heat, pain, tension, and general febrile condition. In passive haemorrhage the blood is venous, as in chronic diseases of the liver, uterus, and rectum. There are certain persons called " bleeders," in whom a haemorrhagic diathesis exists, a peculiar and often hereditary constitutional defect in which the blood seems to have no power of coagulation and the vessels none of contractility; in such the most trifling wounds are followed by profuse and sometimes uncontrollable and fatal bleeding.

The symptoms of haemorrhage vary according to its seat, whether external or internal, active or passive; the amount of blood lost is almost always greatly overestimated by terrified patients and bystanders. In most acute attacks there are premonitory symptoms, constituting the so-called molimen hoemorrhagicum, such as chills followed by heat and fulness of the vessels of the part. A small loss of blood may produce great relief in congestions and inflammations, but haemorrhage carried beyond this point causes paleness, chilliness, cold sweats, nausea and vomiting, hurried respiration, weak and rapid pulse, dizziness, fainting, and finally convulsions and death. In severe wounds these symptoms may in a few moments end fatally; at other times the train may be prolonged for years, with a gradual sinking of the vital forces. In acute inflammations an amount of blood may be taken which would be seriously felt in a state of health. Bouillaud and his disciples of the French school applied the lancet, cups, and leeches in a way that deservedly excited the opposition of other practitioners; Lisfranc, in a case of tetanus, bled a patient from the arm 19 days in succession, and applied nearly 800 leeches along the spine.

The loss to the system from profuse bleeding is very soon made up, and the sooner in proportion to the rapidity of the abstraction, in a healthy person; while the feebleness arising from frequent but inconsiderable haemorrhages may require years for its removal. Modern practitioners generally avoid venesection except in inflammatory and congestive diseases of threatening character, as where the brain, heart, and lungs are in momentary danger; arterial sedatives (like digitalis and veratrum viride), and revulsives to the skin and mucous membranes, have nearly taken the place of the lancet and the leech. Bleeding from the nose is most frequent in the young, from the lungs between the time of puberty and adult age, and from the rectum, bladder, and uterus later in life. The prognosis of haemorrhage varies according to its origin and amount, and the constitution of the individual. While an effusion of blood into the brain or the pericardium would be very dangerous, a bleeding from the nose or from piles would be generally of little importance; blood coming from the stomach and urinary organs is a graver symptom than that from the air passages; a rapid is more dangerous than a slow loss to the same amount, and a passive than an active haemorrhage. - The treatment of haemorrhage, exclusive of strictly surgical means, consists, in the active forms, of general and local depletion, cold and astringent applications; the administration of digitalis and veratrum viride to quiet the circulation; of common salt, especially in bleeding from the lungs; of the mineral acids, chloride and sulphate of iron, vegetable astringents, as tannin, and sometimes ergot of rye; and rest and elevated position of the bleeding part when practicable.

Arterial haemorrhage may be known by the florid color, profuse quantity, and pulsating jet of the blood. Nature's processes for arresting such a flow are the contraction of the divided orifice, the retraction of the vessel into its sheath, the coagulation of the blood in and about the sheath, and the retardation of the circulation by faint-ness; and these will generally suffice for the wound of an artery of the size of the temporal. When art interferes, it is by pressure, torsion, the ligature, cold, styptics, and caustics; a partial is more dangerous than a complete division of an artery, as contraction and retraction are prevented, and for this reason a small vessel should be completely divided. A lacerated artery contracts almost immediately, and rarely bleeds; hence the umbilical cord of animals bitten or torn by the mother gives forth no blood, and hence the efficacy of torsion. Haemorrhage from a vein is continuous and darker colored, and rarely dangerous, unless from a large, deep-seated, or varicose vessel; pressure, elevated position, and styptics will generally arrest it, and as a last resort the ligature. Bleeding from the nose may be either arterial or venous, and requires nothing special beyond snuffing up astringents and plugging the nostrils.

In each case the treatment must depend upon the seat of the lesion, and other circumstances, which require either topical or general remedies. Whenever topical applications are admissible, they are the most efficient. - For haemorrhage of the lungs and rectum, see Haemoptysis, and Haemorrhoids. Bleeding from the stomach is hoematemesis, and that from the uterus metrorrhagia, or Menorrhagia' when connected with the menstrual discharge.