fection takes place through a broken cutaneous surface, and leads to a
superficial lymphangitis with nodular thickening of the lymphatics
(_farcy buds_). The neighbouring glands soon become swollen and
indurated. The primary lesion meanwhile inflames, suppurates, and, after
breaking down, leaves a large, irregular ulcer with thickened edges and
a foul, purulent or bloody discharge. The glands break down in the same
way, and lead to wide destruction of skin, and the resulting sinuses and
ulcers are exceedingly intractable. Secondary deposits in the
subcutaneous tissue, the muscles, and other parts, are not uncommon, and
the nasal mucous membrane may become involved. The disease often runs a
chronic course, extending to four or five months, or even longer.
Recovery takes place in about 50 per cent. of cases, but the
convalescence is prolonged, and at any time the disease may assume the
characters of the acute variety and speedily prove fatal.

The _differential diagnosis_ is often difficult, especially in the
chronic nodules, in which it may be impossible to demonstrate the
bacillus. The ulcerated lesions of farcy have to be distinguished from
those of tubercle, syphilis, and other forms of infective granuloma.

_Treatment._--Limited areas of disease should be completely excised. The
general condition of the patient must be improved by tonics, good food,
and favourable hygienic surroundings. In some cases potassium iodide
acts beneficially.

ACTINOMYCOSIS

Actinomycosis is a chronic disease due to the action of an organism
somewhat higher in the vegetable scale than ordinary bacteria--the
_streptothrix actinomyces_ or _ray fungus_.

[Illustration: FIG. 30.--Section of Actinomycosis Colony in Pus from
Abscess of Liver, showing filaments and clubs of streptothrix
actinomyces. x 400 diam. Gram's stain.]

_Etiology and Morbid Anatomy._--The actinomyces, which has never been
met with outside the body, gives rise in oxen, horses, and other animals
to tumour-like masses composed of granulation tissue; and in man to
chronic suppurative processes which may result in a condition resembling
chronic pyaemia. The actinomyces is more complex in structure than other
pathogenic organisms, and occurs in the tissues in the form of small,
round, semi-translucent bodies, about the size of a pin-head or less,
and consisting of colonies of the fungus. On account of their yellow
tint they are spoken of as "sulphur grains." Each colony i