Warts, corns, bunions, wens, moles, bony enlargements, fibrous and fatty tumors, are all unsightly, and the last named may be considerably inconvenient. But they do not of themselves tend to undergo such increase or morbid changes as to be dangerous to life. They may therefore, by comparison, be called innocent growths.

Malignant tumors are generally included under the name cancer. They tender to grow indefinitely, at the expense of the neighboring parts and of the general system. They often change their character, becoming open, discharging, offensive sores ; the seat, moreover, generally of severe pain. At last, the whole body of a cancerous patient becomes unhealthy ; and the end, after vari ous periods, is death.

Cancers may be either schirrus, colloid, or encephaloid. Schirrus is hard cancer. Colloid is jelly-like. Encephaloid is soft, almost like brain substance.

The parts of the body most liable to be attacked by cancer (especially after middle life) are the womb, the female breast, the stomach, and the lower bowel {rectum) ; but various other organs are sometimes invaded by it. Schirrus is most apt to be met in the breast, stomach or bowel ; colloid, in the stomach, bowel, or covering of the bowels {mesentery, peritoneum). Encephaloid may occur in any organ ; it is the only kind ever seen in the eye, liver, kidney, lung, etc.