Although the mode of performing venesection be known to everybody, yet, in order that no part of surgery may be omitted, and for the sake of its technical distinctions, it must not be overlooked by us. The first object then in venesection is the evacuation of a fulness of blood. It has been shown that fulness of blood is of a twofold nature: first, with regard to the strength, although the veins do not appear full, in which case those affected soon become weak and enervated, nature not being able to support, as it were, the load; and second, with regard to the containing vessels, as is seen in the parenchymatous parts, in which case, although the strength seems able to support the fulness without stress, the vessels sometimes burst, and a spitting of blood or some other discharge takes place. Plethora then as regards the strength may be ascertained from the heaviness upon the body; and plethora of the veins from their distension and from their appearing full. In both cases evacuation is indicated; and, therefore, if necessity require, you must bleed on the first attack of the disease, waiting only for the digestion of the food in the stomach, or the complete sanguification thereof in the liver. But if on any account venesection has not been had recourse to in the beginning, and has been postponed until after the seventh day, there will be no impropriety of bleeding even then when necessity requires it, and the strength does not contra-indicate. But when about to let blood it is necessary to ascertain that there be not a great obstruction of fæces in the intestines, and, if there be, the bowels ought first to be evacuated by an emollient clyster, lest the veins of the intestines suck in the putrid matter of the excrements. Those requiring the abstraction of blood from the presence of a disease we may bleed at any season, avoiding only the acme of particular paroxysms in fevers. But if it be a continual fever, the morning is by all means the fittest season for the operation. Those who require the evacuation of blood, not from the presence of any disease, but as a preventive, will find the spring the fittest season of the year. With regard to age, bleeding must not be practised before the fourteenth, nor after the seventieth year, unless some urgent necessity compel us. And upon the whole we must avoid bleeding those persons whose strength is reduced. In recent inflammations we must make the evacuation from the opposite parts, but in chronic from the adjoining. We abstract blood from many parts of the body, but more especially from the inner part of the elbow. But it is to be recollected that in general the artery lies below the inner vein called the alar; that below the middle one (median) there is a nerve; whereas the upper one, called also the humeral, is free from all risk. In diseases of the head we open the humeral, but in those below the neck, the alar. The median is applicable in both cases.