Extravasation arises from the bursting or breaking of one or more of the blood vessels, after contusions, fractures, and other injuries of the head, as well as other parts of the body : this accident is attended with such a copious discharge of blood, as frequently occasions the most violent pain, and death itself, unless the patient be timely relieved.

As soon as the seat of the injury is discovered, the extravasted blood should first be discharged ; after which the wound is to be cleaned, and all splinters or foreign bodies extracted. The assistance of a surgeon is, on this occasion, immediately required, because a vein must be opened, and as much blood taken away as the patient's strength will permit; by which the extravasation of more blood is prevented. A brisk laxative is next to be given, to lessen the quantity of the fluids ; the head is to be fomented with medicated bags ; and a plaster of melilot applied to it; while volatile salts, or spirit of hartshorn, may he held to the patient's nostrils ; and decoctions of betony, lavender-flowers, or other attenuating liquids are administered, in order to support his strength. These applications will hot, probably, be effectual at first; but they should be continued, especially if the more alarming symptoms appear to abate. And, if the patient seem to have received benefit from the bleeding, it will be proper to repeat it a second, or even a third time, particularly if he be of a robust and plethoric constitution. Meanwhile, no animal food, nor any stimulating liquors should be used, and every degree of mental and bodily irritation should be carefully avoided.