The most malignant and intractable of tumours is the Carcinomatous. This term is applied to the disease in its occult state, whilst Cancer, a term pretty indiscriminately employed, may denote its condition after ulceration. The word scirrhus is often used synonymously with carcinoma; but the former has been, and still is, improperly employed to denote indurations and enlargements of structures in all situations, and has been altogether so much abused as to warrant its being erased from the nomenclature of diseases. Carcinoma seldom occurs before the age of thirty, and generally not till a later period of life; there are instances, however, of its appearance at a much earlier period. Very frequently it is not primary, but supervenes on adventitious formations originally of an innocuous character, and which might have long remained so. All tumours, though at first not of a hurtful tendency, are liable to assume malignant action, either from a constitutional cause, from external injury, or from latent disposition. When it occurs in newly-formed parts, the surrounding cellular substance is frequently condensed and thickened, so as to form a cyst round the tumour; and when it supervenes on chronic tumours, the cysts which enveloped these remain, for some time, as entire and distinct as formerly, though the character of their contents is remarkably changed. Afterwards the cyst may be contaminated with the same disposition as its contents, assume the same action, and be converted into a similar substance. When the disease is seated in the lymphatic glands, the cyst is at first distinct, and gradually disappears; whilst in this affection of the conglomerate glands a cyst is at no time perceptible, and the cancerous matter insinuates itself, and is lost, in the surrounding substance. The carcinomatous tumour is of great density, and communicates a peculiarly grating sensation and noise when cut. In its section there appears a central point, or nucleus, from which dense ligamentous bands of a white colour proceed towards the circumference, diverging in regular succession, as rays of light from a luminous body; or the larger bands subdivide into smaller ones, which follow a similar course with their parent trunk, or ramify regularly; or, from the first, follow an irregular and intricate course, uniting with and crossing one another, so as to present a retiform appearance. In general, the interposed substance is of a greyish colour, extremely dense, and generally homogeneous, though sometimes granular. Often the ligamentous bands are so numerous, and so intimately interwoven, as to leave little or no room for any intervening substance. Sometimes, and most frequently in the advanced state of the tumour, the greyish matter appears to have been broken down and removed, its situation being occupied by a glairy or turbid fluid, by a soft pulpy substance, or by blood; the parietes of such cysts are formed