Lacerations of the larger arteries, arising from traumatic influences, as from concussions and contusions of the body, are only interesting in a scientific point of view, when the different mechanical modes of laceration affect indifferently the separate arterial coats, and when they resemble certain spontaneous lacerations. Such is the case when the laceration implicates the two inner coats of the vessel (the lining and yellow membrane), while the cellular sheath of the vessel is in a state of integrity, or when the separation of its continuity does not correspond in extent, form, and direction with this laceration.

In this respect we must regard with special interest the Icesiones con-tinui, which are owing to some influence limited to a circumscribed portion of an artery, or to a loosening of the cellular sheath and a laceration of both its inner membranes owing to the same influence. They present the greatest similarity with that spontaneous laceration which is termed dissecting aneurism.

Spontaneous lacerations1 may be classified under the following heads.

1. The laceration depends upon a delicacy of construction of the whole arterial wall, and on the generally simultaneous narrowness (insufficiency of calibre) of the vessel; or on congestion, or excessive expansion of the mass of the blood. We have observed several cases belonging to this class.

2. The laceration depends upon a diseased condition of the texture of the coats of the arteries.

The cases belonging to this class form two distinct series.

a. In those of the first series, the Icesio continui consists in a detachment of the cellular sheath from the tube of the vessel, and of a laceration of the middle and lining coats of the vessel within the detached cellular sheath. The question here arises, which of the two is the primary and at the same time the controlling cause?

Experiments prove that it is by means of the cellular sheath, more especially of its elastic longitudinal stratum, that the artery is able to resist any violent lacerating action, and to sustain the force of the blood-wave when the texture of the inner layers, particularly of the yellow coat, is in a state of integrity.

In the above cases, the alteration of texture consists essentially in a chronic inflammation of the cellular sheath, which causes it to be more easily detached. The cellular sheath is here loosened, over various extents of surface, from the tube of the vessel, either alone or with an adhering layer of the yellow membrane, which is generally torn transversely, and only very seldom longitudinally to the vessel. The yellow coat is very brittle in the cases to which we refer, and where this condition was certainly the result of advanced age, this membrane admitted readily of being separated. The lining membrane was for the most part diseased, although only in a moderate degree, exhibiting a deposit which was partially ossified. - By way of elucidation we will give a case borrowed from the memoir before referred to.

A. G. v. P -, aged 52 years, a widow, fell to the ground in the street, on taking a quiet walk after dinner, towards evening, on the 18th of February, 1833. After being bled, she was carried to the hospital. She vomited twice, and after momentary recurrences of consciousness, died on the following morning, after long-continued and profound syncope.

Autopsy

The body was of moderate size and thin.

The walls of the cranium were 3-4'" in thickness and compact; on the left parietal bone, above the semi-circular line, a compact exostosis was discovered, about the size of half a walnut; the inner cerebral membranes were infiltrated. Some of the arteries on the base of the brain were partially ossified.

1 Oesterr. med. Jahrb., Bd. xvi. St. 1.

The lungs, with the exception of the swollen anterior margins of their upper lobes, were of a dark red color, rich in blood, and oedematous at different points. The left pleural cavity contained 1 lb., and the right cavity about 4 oz. of pale reddish sanguineo-serous fluid.

There was considerable extravasation of coagulated blood in the posterior mediastinum round the aorta and the oesophagus, more especially, however, round the pulmonary vessels and the branches of the trachea, towards the roots of the lungs; the pericardium contained upwards of a pound of coagulated and fluid blood.

The heart was somewhat larger than usual, nearly of a round form; the left ventricle and the Conus arteriosus were very large, and the walls of all the cavities were of normal thickness. The right side of the heart was covered with a considerable layer of fat; the ramifications of both the coronary arteries were, for the most part, ossified. The substance of the heart was pale and friable.