Aneurism, in surgery, signifies a throbbing tumor, occasioned by the dilatation or rupture of an. artery : it consists of* three kinds. viz. the true or encysted, the false or diffused; and the varicose.

The true aneurism, when situated near the surface of the body, produces a rumor, at first small and circumscribed, but, when pressed by the finger, it manifests a distinct pulsation. By degrees it increases, and becomes more prominent ; still, however, the patient does not complain of any pain. As. it grow- larger, the skin turns more pale than usual, also more phlegmonous, or swollen, and assumes a livid and gangrenou pearance. A bloody serum now-oozes through the integuments; the skin cracks in several places ; and the artery, being deprived of the usual resistance, discharges its blood with such velocity; as to occasion almost instantaneous death.

The false aneurism consists of a wound or rapture of an artery, and, by the extravasation of blood, produces a swelling of the contiguous parts. If not improperly treated by constant and close pressure, it generally remains nearly of the same size, for several weeks In-stances have occurred, where the blood has diffused itself over the whole arm in a few hours ; as, on the contrary, swellings of this kind have been months, nay, even years*, in arriving at anyconsiderable size.

The varicose aneurism is that which ar ses from the puncture of an artery, and sometimes happens in blood-letting. This circumstance it is hoped, will point out the necessity of persons applying to regular practitioners, who are acquainted with the situation of the blood-vessels, and not employing as is too frequently the case, ignorant and unskilful pretenders, for the formance of this important operation : soon after the injury has been committed, the vein which immediately communicates with the wounded artery, begins to swell, and gradually to enlarge. Upon pressure, the tumor di appears, because the blood contained in it is poshed forwards in its circulat on to the heart; and when large, there is a singular tremulous monon, attended with a hissing noise, as if air were passing through a small aperture.

The causes which generally pro-duce aneurisms, are a peculiar predisposition of the arteries, when they are in a relaxed state ; a partial debility of their coats ; excessive bodily exertions; stooping, and lifting great weights; acrid-matter contained in a neighbouring sore ; intemperance, etc. Where they arise from any external accident, an operation may be attended with success ; but, in all other cases, art ean afford but little assistance.

in a complaint of this- nature, it is presumed that the earliest application will be made to professional men ; and as the narrow limits of this work do not permit us to enter into a more minute investigation, we shall close this article with describing a new method of treating an aneurism, recommended by Mr. Lambert, surgeon at Newcastle uponTyne, in a letter to Dr. Hunt-PFw This was successfully practised, by passing a steel pin, one-fourth, of an inch in length, through the lips of the wounded artery, and then securing it in the Same manner operation for the hare-lip. a thread round it. It was performed on the 15th of June, 1763, and on the 19th of the following month, the patient was dis-missed, perfectly well 5 the pulsa tion of that arm remaining nearly as strong as in the former.