Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 1, 1802).djvu/325

295&#93; BLO when they are shedding their teeth, as it allays those feverish heats to which they are subject at that pe- riod ; but the cases that more par- •iieularlyrequire bleeding, are colds, falls, injuries of the eyes, strains, and all inflammatory disorders. These noble creatures should al- ways be bled by measure ; two or three quarts are generally a suifi- cient quantity ; and when vene- section is repeated, strict attention should be paid both to the disease and constitution of the animal. BLOOD-VESSELS, in anato- my, are long membranous canals, which convey the blood through every part of the body. They are divided into two classes, arteries and veins. For an account of the construction, situation, and uses of the former, see Artery. The veins originate from the ex- tremities of the arteries, and return the blood from them into the au- ricles of the heart, which is the common termination of all the veins. Like the arteries, the veins are also composed of three mem- branes, but more delicate than those of the former, and nearly transpa- rent; they are divided into trunks, branches, ramtili, See. In general, the veins are situated by the sides of the arteries, but mere superficial- ly ; and as they proceed towards the heart, they gradually become larger. As tire veins do not pulsate, the blood, which they receive from the arteries, is urged forward partly by the contractility of their coats, partly by the pressure of the blood from the arteries, and partly by respiration. They are moreover furnished with valves, which pre- vent the return of the blood. — See Blood. BLOODWORT, die Small- grained Dock, or the Rumex san- BLO [2 9S guineus, L. is a plant seldom cul- tivated, as it so quickly propagates that it becomes a troublesome weed. See Withering, 353. The fresh leaves and stalks of this vegetable afFord a juice of a dusky blood-red colour ; which, after standing for a short time, changes to a dark blue or violet tint : and if prepared with alum, it might pro- bably be used in dyeing. This juice, when laid over other colours in painting, imparts to them an addi- tional lustre, and may be used, if properly mixed, either as a red or blue colour. Bloody Flux. See Dysentery. BLOSSOM, in general, signi- fies the flowers of plants. See Flower. It is also applied to the flowering of trees in the spring, called their bloom. The use of the blossom to the vegetable is, partly to protect, and parUy to draw nourishment for the embryo fruit or seed. Blossom is also a term applied to a horse, whose general colour is white, but interspersed with sorrel and bay hairs. Such horses are so insensible, and hard both in the mouth and flank, that they are scarcely of any value; and are likewise very liable to turn blind. BLOW-PIPE, in chemistry and mineralogy, an instrument by which the breath may be directed in a stream upon the flame of a lamp, or candle, in order to vitrify a small quantity of mineral substance. The process of assaying in the dry way, may readily be performed in the same manner. Most of the experiments which can be made by means of a large apparatus, may also be accom- plished by the blow- pipe, in a much shorter space of time, while even die smallest particle of Lhe^ matter V 4 in