It is a common opinion, that the blood ought to be taken, if possible, from a vein which arises from, or near the affected part; that, for instance, in phrenites, we should bleed in the jugular vein; in inflammation of the feet, we should bleed in the leg, &c.: And, when this can conveniently be done, it may be preferred; because, it not only possesses all the advantages of general bleeding from any other vein, but also may be supposed to produce, in a slight degree, a topical evacuation. If, however, the veins be so small, that we cannot detract enough of blood, and sufficiently quickly; or if, from any other cause, we cannot do so, then, if the general action be violent, we must have recourse to another vein, as the loss to be sustained, by confining ourselves to this vein, is infinitely greater, than any good which can be derived from it, as a local evacuation. Indeed, when we consider the laws of the circulation, we must allow, that very little good can be done in this way, as a local detraction; because one vein does not lose more blood than another, except during the moment of the flow. The blood, when drawn during inflammation, has always a buffy coat, which is, in general, thicker, and more concave, in proportion to the violence of the inflammatory action; and the continuance of this condition, is one circumstance which points out the necessity of continuing our evacuation: But the mere existence of a buffy crust, is not, without these circumstances, any infallible sign of the necessity of bleeding; because this crust is to be found on the blood, after the inflammation has begun to become passive; and it is to be found also, when mortification is approaching; we observe it likewise very frequently upon the last cup of blood which we find it necessary to take away. In these cases, however, the crust is much softer, generally thinner, always flat, instead of concave, and looser in the texture; it is also more of a greenish hue. These circumstances, conjoined with the state of the pulse, will enable us to judge, whether we should totally desist from, or continue our evacuations with caution. Most frequently they forbid farther bleeding.