EMBOLISM (derived from the Greek word embolon, -± plug) is the term employed by recent pathologists to designate the plugging-up of a vessel by a clot of coagulated blood fibrin, by a detached shred of a morbid growth from a diseased cardiac valve, etc. It is in cases of ill-nourished, broken-down constitutions, or after a protracted or a debili • tating illness, that the morbid tendency of the fibrin to coagulate spontaneously within the veins chiefly exists, and in such cases very trivial circumstances may call it.forth, especially if they lead to any pressure on the vessel. Clots, or portions of a clot, may be transported by the blood-current from the venous system to the right side of the heart, and block up the pulmonary artery either entirely or in part: if the occlusion is entire, sudden death is produced; while, if it is only partial, gangrene, or inflammation of a part of the lung, commonly ensues. Many of the sudden deaths of women in child
bed (till recently quite inexplicable) are due to this cause, the plug being formed in the inflamed uterine veins, or possibly, in some cases, in the. right side of the heart, and passing from thence to the spot where its arrest proves suddenly fatal. Several cases of this kind are reported in Simpson's Obstetric Memoirs. Similar accidents may happen in the arterial system. A detached fragment of a diseased tricuspid or aortic valve of the heart, or a separated fragment of coagulated fibrin, may be driven onwards in the blood-current, and enter and occlude some of the cerebral arteries, causing softness of the brain, by cutting off the due supply of nourishment. For further details, the reader is referred to an exhaustive treatise on this subject published a few years ago by Cohn, entitled Ueber em,bolischen. Krankkeiten.