Aneurism is generally a disease of middle life, being most frequent between the ages of thirty and fifty, although it has occasionally been met with even in children.

The predisposing cause of aneurism is usually some constitutional tendency to arterial disease, which may perhaps be created by intemperance, syphilis, or the abuse of Mercury. The exciting cause may be, strong emotion of the mind, violent exertion of the body, or local injury. Men are very much more subject to it than women.

If an aneurism be seated in the neck or limbs, it appears as a swelling in the course of an artery, and pulsating with it. If it be small, and not filled with coagulum, pressure on the artery above will render it flaccid, so that it may be emptied by pressure; and when the pressure is removed the blood returns into it with a peculiar vibratory thrill. The patient will very often say that it commenced after some violent strain, when something appeared to give way. In the chest, aneurism will be principally known by an unnatural pulsation felt by the patient, and detectable by the stethoscope; together with symptoms of disordered circulation and respiration. In the abdomen an aneurism may be felt by laying the hand over the part affected. An aneurism has occasionally been caused through carelessness in performing the operation of bleeding in the arm; the artery being punctured through the vein. Tumours situated over arteries, and receiving pulsation from them, may be distinguished from aneurism by noticing, first, that they do not pulsate at first, when they are small; whereas aneurisms do so* from their earliest formation. Secondly, that a tumour may often be lifted up from the artery, and that then it will cease to pulsate. Thirdly, that aneurisms are generally soft at first, and become hard subsequently; whereas tumours are generally the reverse. Fourthly, that tumours cannot be emptied by pressure, and that no alteration is made in the consistence by compressing the artery above.

As an aneurism enlarges, its coats become thinner, but are strengthened by the adhesion of the parts around. As the enlargement proceeds, these are gradually absorbed; bone offers no resist-ence, but is absorbed as well; and at last the tumour reaches the skin and distends it. Inflammation succeeds; the skin becomes red, then livid and vesicated; and at last sloughs. When the slough separates, a fatal bleeding ensues; sometimes in a gush enough to destroy life at once, although more frequently the blood oozes away slowly. In the case of the late Mr. Liston, (the eminent Surgeon,) who died of aneurism of the aorta, the fatal issue of the disease was delayed for more than six months, after a single occurrence of profuse haemorrhage from the mouth. But an aneurism may burst into a mucous canal; or into a serous cavity; or into a vein, with, of course, a fatal disturbance of the circulation, if the vein is large; or into the cellular tissue of a limb; or it may cause death through its pressure on the trachea or oesophagus; or through the pain and irritation created by its compressing nerves or interfering with the abdominal viscera, without bursting.

In some fortunate cases a spontaneous cure occurs, either by the coagulation of the blood contained in the sac, and the conversion of the aneurism into a firm tumour, (in some cases, however, the sac does not become quite obliterated, but the coagula become thick and firm enough to resist further distension), or the aneurism has sometimes sloughed or been involved in a large abscess, and the artery participating in the inflammation has become obstructed by effusion of lymph, or by coagulation of the blood in it. It has happened that a portion of clot has been detached from the interior of the sac, by some accidental violence, and has effected a cure by blocking up the opening into the aneurism. Occasionally the artery in which the aneurism has been formed has become obliterated by an accidental pressure of the aneurism upon it; or by the pressure of blood escaping from it, on its bursting into the cellular tissue.

It appears, from an examination of nearly 900 cases of aneurism, that those cases which end with rupture of the sac are attended during life with less formidable symptoms than those which kill without rupture; and sometimes with no symptoms at all. The patient may seem, and may believe himself to be, in perfect health. The reason of this is obvious enough. Rupture is often prevented by some opposing part, upon which the enlarging tumour makes distressful pressure.

Treatment

Surgical treatment. If the aneurism throbs painfully, and is rapidly on the increase, and the patient is plethoric, it is recommended to take a moderate quantity of blood from the arm, although, in the present day, it is generally agreed that to abstract blood to such a degree as to weaken the patient is not good practice. Afterwards, if it can be done, the great measure is to tie the artery between the aneurism and the heart, thus cutting off the supply of blood. After the operation, the temperature of the limb falls two or three degrees, but in a few hours it rises rather higher than that of the opposite limb, because the blood is forced to circulate through the superficial vessels. Subsequently, it sinks again rather below the natural standard. Therefore the patient should be placed in bed, with his limb in an easy position; and though it become rather swelled, which is not unlikely, cold must on no account be applied.

When a ligature cannot be applied between the aneurism and the heart, it has been proposed to tie the vessel on the other side-of the swelling; and this operation has been performed with success by Mr. \Wardrop and others, in cases of aneurism of the Carotid artery. But Mr. Guthrie shows that this operation does not act like the ligature between the aneurism and the heart, by stopping the circulation through the aneurism; but by giving rise to inflammation in the aneurism, and in the artery both above and below it, and that, unless it does this, it fails. It is therefore a dangerous and uncertain operation, and should be performed only where the tumour increases rapidly, and cannot be checked by any other means.

After the operation the limb may become gangrenous. If the gangrene spreads beyond the fingers and toes, amputation should be performed above the level of the ligature.

Cases have been published in which a cure has been effected by pressure, applied either to the aneurism itself, or to the artery above it.

The medical treatment that must be adopted when no operation can be performed,consists in such measures as will reduce the heart's action, without diminishing the strength of the patient. Bleeding by means of leeches over the seat of the complaint may be resorted to occasionally, if the patient is plethoric, and the tumour increases rapidly, with violent pulsation; but it should never be carried so far as to produce faintness. The diet should be light and nourishing, but fermented liquors should be rigidly abstained from, as well as both bodily and mental exertion. Particular care should be taken not to administer drastic purgatives, as they invariably cause a great excitement and throbbing of the arteries. If the bowels are confined therefore,they should be regulated with Castor Oil, or with small doses of Milk of Sulphur (a teaspoonful) taken every morning before breakfast.

The greatest benefit has been derived in aneurism from Digitalis in small doses, and particularly from the Acetate of Lead. This last medicine is said to have the faculty of rendering the blood coagu-lable, and of diminishing the calibre of the arteries. It used to be strongly recommended by Mr. Green, in his lectures at King's College. The following preparations may be taken:

Acetate of Lead in fine powder..................12 Grains.

Powdered Opium..................................6 Grains.

Crumb of Bread sufficient to mix with. Divide into 24 pills; one of which may be taken three times a day, along with a tablespoonful of the following mixture:

Tincture of Digitalis...............Two Drams and a half.

Sweet Spirit of Nitre..............One ounce.

Infusion of Wild Cherry sufficient to make Half a Pint.