, or as embolisms. In such cases their
sole character depends wholly upon the kind of cancer from which they have
sprung. The infiltrating cancer begins as an elevation of the skin, which
progresses until it becomes rough and nodular. The surface later becomes
attacked, and an ulcer results whose edges are outlined by a hard, firm
zone.

The ulcerations may remain limited by cicatricial tissue, but it is more
likely that the infiltration and destruction of tissue will spread out
wider and deeper until a rodent ulcer (so called) is formed. One of the
most frequent sites of cancer in cattle is in the eye, where they are
called fungus hematodes, but they also occur on the skin, on the genitals,
in the stomach, and within the organs.

_Fungus hematodes._--This starts at the inner corner of the eye as a
papillary elevation or as small nodules which become fused. They grow
larger and become papillomatous, with superficial ulcerations and a
tendency toward hemorrhage. In some cases the eye is displaced by the
growing tumor or is attacked by the cancer cells and entirely destroyed.

Cancerous growths upon the external genitals and the anus usually present a
rough, irregular surface from which there is a constant sloughing of
decomposed tissue accompanied with a penetrating disagreeable odor.

The diagnosis of cancer may be made clinically by noting the simultaneous
infection of the lymph glands which surround the primary lesion. Deeply
burrowing and infiltrating forms which appear as lumps and ulcerations
cause marked disfiguration of the affected part. The surface becomes a
soft, greasy mass; later it cracks open and from the fissures blood-colored
pus exudes, being continually formed by the moist degeneration of the
tissues beneath. At first the general health of the animal does not appear
affected, but later the cancer nodules spread to important organs and give
rise to marasmus and progressive emaciation. Cancer is not a frequent tumor
of cows. Froehner states that of 75 cases of tumors in cattle which came
under his observation 2, or 2.6 per cent, were found to be cancers, while
20, or 26.6 per cent, were sarcomas.

_Treatment._--Treatment consists in the early and complete removal of the
tumor, taking care to include a wide border of healthy tissue. This has
been most successful in such superficial cancers as those of the eye,
penis, anus, testicle, vulva, and sheath. If the disease has advanced too
far, this treatmen