(From within, and pus, or matter). The ancients called all internal suppurations empyema, (see ecpyema); but at present this name is confined to a collection of purulent matter, lying loose in the cavity of the breast, and lodging on the diaphragm. Dr. Cullen considers it as a consequence of pneumonia, and says, its symptoms are, a remission of pain, after a pleurisy has terminated in suppuration, often after a vomica; whilst a difficulty of breathing, cough, uneasiness in lying down, and hectic fever, continue: frequently attended with a sensation of some fluid fluctuating in the breast, and symptoms of a hydrothorax.

Aretaeus, lib. i. De Causis et Signis Morborum Chro-nicorum, cap. 9, says, "They who have purulent abscesses in the cavities of the body, whether within the thorax or below the diaphragm, if the pus be discharged upwards, are called (empyi); if downwards, apostomatici. And if there be a suppuration in the thorax, and the pus be discharged through the lungs, it is called " hut the moderns styled it only an empyema when purulent matter floats upon the diaphragm. If matter is lodged on both sides of the breast, there are two empyemas.

The pus, that forms an empyema, may be from an abscess in the lungs, pleura,mediastinum, pericardium, or diaphragm; or perhaps from that inflammatory exudation, or inspissated serum, which, Dr. Hunter observes, resembles pus, often found in large quantities in the cavities of the breast, belly, etc. Wounds in the breast may also evacuate their matter into its cavity, and prove a cause of this disease. Le Dran informs us, that he met with instances of abscesses in the liver making a way through the diaphragm, and emptying themselves into the breast. Some instances of this have occurred in modern times, and small apertures in the diaphragm, through which pus has passed, anatomists have observed and described. (Pemberton on the Diseases of the Abdominal Viscera, p. 36). From Sauva-ges may be collected six varieties, although they are not always capable of being distinguished, viz. Empyema a peripneumonia; and vomica; empyema pleurae medi-astina; diaphragmatis; and intercostale.

When any fluid matter is collected in the cavity of the breast, it may be known by the following signs: the breathing is short and laborious; expiration is more difficult than inspiration; the patient perceives a fluctuation when he changes his position from side to side, or presses the abdomen against the edge of a table; sometimes there is an enlargement of the cavity of the thorax, and an oedematous fulness of the skin and flesh of one or both sides of the chest; a dry cough; a slow fever; heat at the extremities of the fingers; and hollowncss of the eyes. The patient cannot lie on the sound side, though in hectics he can only sleep easily on it. The Kind of matter can only be known by the nature of the disorder, which preceded an accumulation, and from the concomitant symptoms. The matter may be blood or pus: and the latter of these may be suspected, when there hath been an inflammatory disorder in the lungs, pleura, or other parts in the breast, attended with symptoms of suppuration, and particularly if viscid sweats attend.

If the matter of an empyema be not speedily expectorated, the patient dies of a consumption, with a hectic fever, which is always exasperated at night. If the mediastinum is corroded, upon opening the thorax a sudden suffocation must ensue. If the empyema is of long standing, the strength decayed, with a colliquative diarrhoea, and a wasting of the body, the operation, instead of relieving hastens the death of the patient. When this disorder is merely local, the operation may succeed, but if the habit be strumous, or otherwise unsound; if fever, coughing, thirst and other symptoms, are either numerous or considerable in their degree; there is but little hope of recovery. The operation is also ineffectual if the lungs adhere considerably to the pleura, or if the matter lodged on the diaphragm was emptied from a cyst.

The chirurgical method by which relief is obtained is called the operation for the empyema. The fluid to be voided by this operation is matter. In this case, therefore, only the assistance of a surgeon is required; for blood will be gradually absorbed, and need not be removed by any artificial opening. Gooch relates a case in his Medical Observations of air in the thorax producing the symptoms of an empyema: it passed through an ulcer in the lungs; but the ulcer healing, the air was evacuated by the operation for the empyema, and a complete cure effected.

The manner of operating is to fix on the part for the perforation; then, with a knife or a trochar, a passage may be formed for the offending air. Whether an opening is made by means of a knife or a trochar, as Albinus hath observed that the diaphragm on the right side ascends higher into the thorax than on the left, it may be proper to pierce it on the right side between the third and fourth spurious ribs; but on the left, between the second and third, and at about half or two thirds of the distance from the sternum to the vertebra; for here the muscles are thinnest, the artery is concealed under the rib, and the diaphragm at a due distance. The puncture must be made with the utmost caution, lest there should be an adhesion of the lungs to the pleura; a canula for a time left in the wound, and the wound itself kept open. Matter, lodged in both cavities of the thorax, requires that the operation be performed on each side. See Hippocrates, Galen, Aretaeus, Boer-haave, with Van Swieten's Comments, Le Dran's Operations, Sharp's Operations, Heister's Surgery, Bell's Surgery, vol. ii. p. 383, Kirkland's Medical Surgery, vol. ii. p. 175, Pearson's Principles of Surgery, vol. i. p. 94, White's Surgery, p. 303.