CAUSE.—The excessive action of the heart, when the horse has been distressed by severe gallops or an exciting run, produces a jerking of the whole body, as the heart strikes the dorso-costal region, towards the upper part of the first false ribs. SYMPTOMS.—These are much the same as in Anemic Palpitation; but in addition there is violent elevation of the flanks, perceptible to the observer, and, if being ridden, most unpleasant to the rider. The symptoms appear and disappear suddenly. TREATMENT.—Give A.A. once in two hours, at first, and later three times per day. Embolism DEFINITION.—Distension and plugging of the arteries by solid coagulated lymph, consisting of fibrous clots, fragments of decaying or suppurating tissue, and the elements of Tubercule and Cancer. CAUSE.—The reason why there is deposition of the offending material is unexplained; but it is brought from different parts of the circulatory system, from diseased tissues through the veins and the heart, and deposited so as to obstruct larger or smaller arteries, and thus prevent the flow of arterial blood to the limbs and organs. The arteries and hind limbs are most liable to this disorder. SYMPTOMS.—An accurate diagnosis is not always practicable, because the disease itself is obscure. The symptoms which have been observed attending Embolism are great pain, profuse sweat, but cold extremities; quick, wiry pulse; and considerable general disturbance of health; anxious expression of face; looking round to the affected parts; rigidity and contraction of certain muscles; partial recovery and simultaneous attack of the other limb, and return of attack to the first; diminished pulse in the arteries of the implicated limb; peculiar throbbing of the posterior aorta felt through the rectum; followed by partial or complete paralysis of the limb or hind quarters; and ultimately death. Aneurism DEFINITION.—A tumor formed by the dilatation of an artery, or communicating with an artery, and containing blood. In the first stage the tumor contains fluid blood, and pulsates; in its second stage it contains coagulated blood, deposited in numerous thin layers, resembling the leaves of a book. Aneurism may be idiopathic or traumatic; the latter is caused by injury to the artery. In the idiopathic or spontaneous Aneurism the dilatation may be of considerable extent, or it may be limited, with the coats of the artery intact or even thickened, or the inner coat may be attenuated and the outer one pressed outward. As the Aneurism becomes old, the coats become indurated, calcified and liable to burst. It is not an uncommon disorder in the horse, and when it occurs it is generally in the deep-seated arteries. The posterior aorta, at the origin of the anterior mesenteric artery, is very subject to Aneurism as animals grow older.