HÆMATOCRYS′TALLIN. A crystalline substance obtained by the action of oxygen and afterwards carbonic acid on the ‘clot’ of blood.
HÆMATOS′IN. Syn. Hæmatin, Red pigment of blood. The red colouring principle of the blood. It is not known in a state of purity. It differs from the other animal principles in containing, as an essential ingredient, the sesquioxide of iron.
HÆMATOX′YLIN. A principle obtained by Chevreul from common logwood (Hæmatoxylon campechianum), and on which its colour appears to depend.
Prep. 1. Infuse logwood chips in water, at a temperature of about 130° Fahr., for 12 hours, filter, and evaporate to dryness in a water bath; digest the residuum in rectified spirit for 24 hours, again filter and evaporate; then add a little water; again gently evaporate and set aside the solution in a cold place that crystals may form; these must be washed in rectified spirit and dried.
2. Digest powdered hard extract of logwood in rectified spirit, and proceed as last.
3. Powdered logwood is mixed with sand and digested for several days in pure ether; the resulting liquid is filtered, evaporated to a syrup, and set aside to crystallise.
Prop., &c. Brilliant reddish-white or straw-yellow crystals, soluble in boiling water, forming an orange-red solution which turns yellow as it cools, but resumes its former colour on being heated. Alkalies in excess change its colour successively into purple, violet, and brown; acids brighten it; with the metallic oxides it forms compounds having a blue, purple, or violet colour.
HÆMOP′TYSIS. In pathology, spitting of blood. It generally arises from extreme fulness of the blood-vessels of the lungs, or the rupture of blood-vessels, as a consequence of ulceration; but sometimes it is induced by excessive exertion or external violence. Depletion, aperients, acidulous and astringent drinks, and nauseants, are the usual remedies. Acetate of lead, in small doses, has been recommended for this affection. When this substance is given, it should be accompanied with a sufficient quantity of free acetic acid, to prevent its being converted into the poisonous carbonate of lead in the system.
HÆM′ORRHAGE. Syn. Hemorrhage; Hæmorrhagia, L. A bleeding or flow of
blood. Bleeding may be divided into active, passive, and accidental.—Active hæmorrhage is that arising from a full state of the vessels, or plethora.—Passive hæmorrhage, from general debility of the system, and of the blood-vessels in particular.—Accidental hæmorrhage, from external violence, as blows, wounds, &c. The first generally requires depletion, and the second the usual treatment to establish the general health and vigour of the body. The bleeding from wounds, if extensive, should be arrested by tying the ruptured blood-vessels; or where this cannot be done, and in less important cases, by the application of styptics, as creasote, sulphate of iron, infusion of galls, compound tincture of benzoin, &c.