But the blood in inflammation also undergoes a change, observable after its removal from the circulation, and especially when the system sympathises with the part affected. The blood, it is generally believed and stated, does not coagulate so quickly as in the natural state, or else, it is said, the red globules, being increased in specific gravity, fall rapidly to the lower part of the containing vessel, so that a yellowish crust appears on the surface of the crassamentum or clot; and this appearance is termed the inflammatory or buffy coat. The blood extracted from the veins of a patient labouring under inflammatory fever often appears to coagulate very quickly; but it contains an unusual proportion of fibrin. In certain states of inflammation, this crust is also much contracted, so that its marginal circumference is at a considerable distance from the sides of the containing vessel; its margins also are elevated and inverted; its upper surface is smooth, whilst the under adheres firmly to the coagulum; and in this state the blood is said to be cupped, as well as buffed. The appearance of the buffy coat is not peculiar to the inflammatory state, but is apparently dependent on hurried circulation, however occasioned. It frequently presents itself in blood removed from the circulation during pregnancy, and in several other conditions of the system, apparently altogether unconnected with inflammatory excitement. In these circumstances, however, the contracted or cupped appearance of the coagulum is hardly ever observed. An ignorance of the above fact leads to dangerous practice, inasmuch as certain practitioners will bleed, and continue to bleed, for very equivocal inflammatory symptoms, conceiving themselves fully warranted in so doing by the presence of the buffy coat. This coat is often not so apparent in the blood first drawn as in that afterwards abstracted. In inflammation, as was formerly remarked, a greater quantity of blood not only flows into the capillary vessels, but it also escapes from them, or is extravasated. This may occur with or without rupture of the vessels, and to a greater or less extent, according to the violence of the action, and the texture of the part. When local inflammatory action exists to a considerable degree, the general circulation is more or less disturbed. The heart, and the larger vessels supplying the capillaries, which are more immediately concerned in the local action, subsequently sympathise with the part affected, and, acting with greater vigour than usual, propel the blood into the extreme branches; so that the inflammatory excitement may be said to be gradually communicated by the continuous sympathy, till the whole sanguiferous system becomes subject to its influence. The degree of this general excitement depends greatly on the texture and function of the part primarily affected.