BLOOD-LETTING (VENESECTION).—A very old remedial and thera peutic measure. Certain observers have claimed that animals at times deliberately bite into their blood-vessels in order to abstract blood. This observation is supposed to have prompted similar experiments in man. The old Greek physician Hippocrates, who flourished about 4o0 recommended the procedure for various ills. Alternately combated, praised, used to excess, or almost entirely forgotten, it was gradually aban doned during the latter hall of the nineteenth century. More recently, how ever, it has again attracted attention. At present venesection is resorted to in certain diseases for the purpose of removing the blood from an over filled and exhausted heart in order to lighten its work and increase its strength. It is employed also to relieve congestion of various organs which temporarily contain an excessive amount of blood, and for the purposes of removing poisonous materials and stimulating the production of new blood. The principal conditions in which blood-letting may he of service are pneu monia, pleurisy, heart disease, cerebral h2emorrhage (apoplexy), epilepsy, and a number of intoxications due to endogenous poisons.
Venesection is usually done from one of the large veins of the arm. sometimes from vessels of the foot. The vein is opened with an ordinary scapel, or with a special instrument in which the knife-blade is suddenly pushed into the vein by the aid of a spring. The instruments used must be aseptic. Before opening the vessel. the limb is constricted with a circu lar bandage above the site selected, in order to fill up the veins and make them more readily accessible. The resulting small wound heals within a few days, during which time the limb must he kept quiet. The patient should remain in bed after the operation, in order that the ensuing perspira tion may be utilised to its fullest extent. Fainting-spells or attacks of weakness rarely occur during blood-letting ; but in order to avoid them the procedure had best be conducted in bed. It is not advisable that venesection be undertaken by laymen.