he tail, around the anus, vulva,
udder, sheath, eyelids, and lips. They are readily recognized by their
inky-black color, which extends throughout the whole mass. They may
appear as simple, pealike masses, or as multiple tumors aggregating many
pounds, especially around the tail. In the horse these are usually
simple tumors, and may be removed with the knife. In exceptional cases
they prove cancerous, as they usually are in man.

EPITHELIAL CANCER, OR EPITHELIOMA.

This sometimes occurs on the lips at the angle of the mouth and
elsewhere in the horse. It begins as a small, wartlike tumor, which
grows slowly at first, but finally bursts open, ulcerates, and extends
laterally and deeply in the skin and other tissues, destroying them as
it advances (rodent ulcer). It is made up of a fibrous framework and
numerous round, ovoid, or cylindrical cavities, lined with masses of
epithelial cells, which may be squeezed out as a fetid, caseous
material. Early and thorough removal with the knife is the most
successful treatment.

VEGETABLE PARASITES OF THE SKIN.

(Pl. XXXVIII, figs. 2, 3, 4.)

PARASITE: _Trichophyton tonsurans._ MALADY: _Tinea tonsurans, or
circinate ringworm._--This is especially common in young horses coming
into training and work, in low-conditioned colts in winter and spring
after confinement indoors, during molting, in lymphatic rather than
nervous subjects, and at the same time in several animals that have
herded together. The disease is common to man, and among the domestic
animals to horse, ox, goat, dog, cat, and in rare instances to sheep and
swine. Hence it is common to find animals of different species and their
attendants suffering at once, the diseases having been propagated from
one to the other.

_Symptoms._--In the horse the symptoms are the formation of a circular,
scurfy patch where the fungus has established itself, the hairs of the
affected spot being erect, bristly, twisted, broken, or split up and
dropping off. Later the spot first affected has become entirely bald,
and a circular row of hairs around this are erect, bristly, broken, and
split. These in turn are shed and a new row outside passes through the
same process, so that the extension is made in more or less circular
outline. The central bald spot, covered with a grayish scurf and
surrounded by a circle of broken and split hairs, is characteristic. If
the scurf and diseased hairs are treated with caustic-potash solution
and