Cancer comprises different varieties, the physical characters of which have many points of contrast.

Scirrhus, as that word implies, is remarkable, in its early stages, for its hardness. It is as firm as cartilage, and creaks when cut in two by a sharp knife. The surfaces exposed by its division present a glistening, satiny appearance, and a white, or gray, or bluish-white colour; and both surfaces are slightly concave. Athwart this grayish and semi-transparent substance run opaque intersecting bands.

Medullary Cancer, on the other hand, is remarkable for its softness. It is composed in great part, of a yielding, white, opaque, pulpy substance, having a smoothly lobed surface, and very closely resembling, both in colour and in consistence, the substance of the healthy brain.

Epithelial Cancer affects, in the first instance, some portion of the surface of the body, or of some mucous membrane. It is most frequently found where the skin and the mucous membranes are about to meet. It produces some swelling and deformity of the part, with commonly a granular, wart-like roughness; and the surface thus altered soon becomes moist, with a slight ichorous discharge, or is covered with a scab, or breaks out into ulceration.

These are all what are called destructive or malignant forms of disease, and if a tumour consisting of one variety be amputated, and a fresh growth spring (as too often it does) from the same spot, this secondary growth is frequently of another variety.

"Of all of them it has been ascertained, by much and fatal experience, that occurring in any one part of the body they are liable to appear in various other parts; that they are commonly attended, during some part at least of their progress, with very severe and characteristic pain; that they are incontrollable by any known remedy, and tend always, sometimes slowly, sometimes with frightful rapidity, to augment in bulk; eating away adjoining parts by their invasion and pressure; breaking out, when near the surface, into foul and repulsive ulceration; producing often the most ghastly disfigurement; and ultimately destroying life. Sometimes vital parts are slowly disorganized by the corroding extension of these tumours; sometimes large blood vessels are laid open, and death is suddenly brought about by haemorrhage; and sometimes the powers of life sink gradually under the wearing influence of the disease.

"There is scarcely an organ or texture of the body which is not liable to be attacked by this terrible foe; the brain, the eye, the lip and face, the lungs, the stomach and intestines, the liver, the kidneys, the breast, the womb, the testicle, the bones. But some parts are more often the seat of cancer than others. Among these may be reckoned the female breast, the womb, the stomach, the liver, and the testicle.

"The mode in which cancer originates is uncertain; the modes in which it spreads and multiplies are better understood.

" Cancer often makes its appearance in a single spot near the surface of the body; in the female breast, for instance. We see. and feel it there while it is yet small, and while the general health of the patient seems to be otherwise perfect. Gradually the tumour enlarges, and enlarging it sends out branches which penetrate in various directions among and between the surrounding tissues, grasping them as it were, compressing them, holding them fast, so that the tumour becomes fixed, or moves only with their motion. This contractile property accounts for the slight concavity assumed by both the surfaces exposed when a scirrhus tumour is cut across; it explains also a puckered appearance of the surface of the breast, and a characteristic pulling inwards of the nipple. We see the same tightening effect of the same disease in other parts, especially in the intestines, which are often narrowed as if tied by a string, and sometimes completely and fatally closed in that way. At length the tumour in the breast softens in some places; the glands of the arm-pit become swollen, hard, painful it may be, and filled sometimes with cancerous matter, carried thither, it may be assumed, by the lymphatics of the part; the tumour breaks perhaps through the skin, and presents the shocking spectacle of an open Cancer; the general health gives way, and the skin assumes a peculiar sallow tint.

"The disease is common to all classes and ranks of life, from the lowest to the highest. The annals of our own and of a neighbouring nation tell of its visits to Royal and to Imperial houses, striking with the impartiality of pale death itself," The First Napoleon died of Cancer of the stomach; so did his father and his sister. The late Lord Metcalfe died of Cancer on the face.

From the tables contained in the reports of the Registrar General, it would appear that women are more subject to this fearful disorder than men, in the large ratio of five to two. It fixes chiefly on the organs of reproduction, the breast, the womb, the testicle. These, and the stomach are the principal seats of primary Cancer; and in these same parts secondary Cancer is comparatively rare.

Scirrhus Cancer rarely shews itself in early life; it most commonly commences between the fortieth and fiftieth years; while Medullary Cancer is met with much earlier than any other variety. It is almost the only form of cancerous disease that happens before the age of puberty. Epithelial Cancer is uncommon before twenty.

The mortality from Cancer increases steadily as life advances.

Cancer of the lip has frequently followed the long-continued use of a clay tobacco-pipe in smoking. The frequent contact of coal-soot appears to have the power of producing Cancer; and there is a well known form of the disease which effects the scrotum of chimney-sweeps from this cause. A case is recorded by Mr. Pott of the same complaint on the right hand of a gardener who for years had been in the habit of sprinkling soot over his flower-beds with that hand.