hich, although differing from each
other in many points, have yet certain common characters to which they
owe their special significance.

1. In structure such growths are composed of nucleated cells and free
nuclei together with a milky fluid called cancer juice, all contained
within a more or less dense fibrous stroma or framework.

2. They have no well-defined limits, and they involve all textures in
their vicinity, while they also tend to spread by the lymphatics and
veins, and to cause similar growths in distant parts or organs called
"secondary cancerous growths."

3. They are undergoing constant increase, and their progress is usually
rapid.

4. Pain is a frequent symptom. When present it is generally of a severe
and agonizing character, and together with the local effects of the
disease and the resulting condition of ill health or "cachexia," hastens
the fatal termination to which all cancerous growths tend.

5. When such growths are removed by the surgeon they are apt to return
either at the same or at some other part.

The chief varieties of cancer are _Scirrhus_ or hard cancer,
_Encephaloid_ or soft cancer and _Epithelial cancer_.

Scirrhus is remarkable for its hardness, which is due to the large
amount of its fibrous, and relatively small proportion of its cell
elements. It is of comparatively slow growth, but it tends to spread and
to ulcerate. Its most common seat by far is the female breast, though it
sometimes affects internal organs.

Encephaloid is in structure the reverse of the last, its softness
depending on the preponderance of its cell over its fibrous elements.
Its appearance and consistence resemble brain substance (hence its
name), and it is of such rapid growth as to have given rise to its being
occasionally termed _acute cancer_. Its most frequent seats are
internal organs or the limbs. Ulceration and haemorrhage are common
accompaniments of this form of cancer.

Epithelial cancer is largely composed of cells resembling the natural
epithelium of the body. It occurs most frequently in those parts
provided with epithelium, such as the skin and mucous membranes, or
where those adjoin, as in the lips. This form of cancer does not spread
so rapidly nor produce secondary growths in other organs to the same
extent as the two other varieties, but it tends equally with them to
involve the neighbouring lymphatic glands, and to recur after removal.

Cancer affects all parts of the body, but