This is a pulsating sac, filled with blood, which communicates with an artery. True aneurism consists of a sac formed by one or more of the arterial coats.  False aneurism is owing to a complete division of the arteria coats, either fom a wound or external ulceration; the sac formed of cellular tissue. Every artery may be effected with any aneurism, but the aorta, carotids, axillary, brachial, iliacs, femorals, and popliteals are the arteries most commonly affected. The tumor at first is small, gradually increasing, soft and quite compressible, being filled only with fluid blood. It pulsates syncronously with the the heart, and is increased by pressure on the side furthest from the heart. A peculiar thrill is imparted to the hand, and which can be heard if the ear is applied. The strength of the part is much impaired as the tumor enlarges, and the circulation in the extremity weaker. During the progress of the tumor the adjacent parts are displaced and absorbed, even bone is rendered carious and absorbed by constant pressure of the aneurism. The pain and numbness increase, and the general health fails, and at length the tumor may burst, opening upon the skin or somc internal cavity, and prove fatal.

TREATMENT. -- Complete rest, and the frequent application of hot-packs to the tumor should at first be prescribed. A stimulating liniment may be rubbed over the part. One composed of the compound tincture of myrrh and the oil of origanum answers the purpose well. The "Herbal Ointment" is an excellent application. The gentle application of electro-galvanism should be resorted to if the above treatment does not suffice. Pressure by well-secured pads, or by the thumbs and fingers, continued for a long time, is often tried and successful in some cases. If the above treatment fails, some competent surgeon should be consulted, who will in practicable cases ligate the artery. Valsalva had a curious plan of treatment for aneurism. It consisted of repeated blood-letting, with food enough merely to support life. A cure worse than the disease.