Actinomycosis, also known as lumpy jaw, big jaw, wooden tongue, etc., is a
chronic infectious disease characterized by the formation of peculiar
tumors in various regions of the body, more particularly the head, and is
due to the specific action of a certain fungus-like germ (actinomyces).
This fungus is an organism which occurs in the tissues in the form of
rosettes, and it has therefore been termed the "ray fungus." The disease is
not directly transmitted from one animal to another, but it seems apparent
that the fungus is conveyed into the tissues by various feedstuffs through
slight wounds of the mucous membrane of the mouth, decayed teeth, or during
the shedding of milk teeth. The ray fungus is found in nature vegetated on
grasses, on the awns of barley, the spears of oats, and on other grains.
Quantities of the fungi have been found between the vegetable fibers of
barley which had penetrated the gums of cattle and on the awns of grain
embedded in the tongues of cows.

Although actinomycotic tumors on cattle had been the object of study for
many years, it was not until 1877 that the constant presence of actinomyces
was pointed out by Bollinger, of Munich, and since that time considered the
cause. This fungus was observed in these tumors as early as 1860 by
Rivolta, and by others subsequently, without having been suspected as
causing them.

Since Bollinger's publication much work has been done, many observations
made, and many hitherto obscure disease processes brought into relation
with this fungus. Furthermore, a similar disease in man was first
definitely shown to be associated with the same fungus in 1878 by Israel,
and in the following year Ponfick pointed out that the disease described by
Bollinger in animals and that found by Israel in man were due to the same
cause; that is, that the fungi described by these observers were one and
the same.

The tumors and abscesses wherever they may be are all found to be the same
in origin by the presence of the actinomyces fungus. When they are incised,
a very close scrutiny with the naked eye, or, at most, a hand lens, will
reveal the presence of minute grains which vary from a pale-yellow to a
sulphur-yellow color. They may be very abundant or so few as to be
overlooked. They are embedded in the soft tissue composing the tumor or in
the pus of the abscess. With a needle they are easily lifted out from the
tissue, and then they appear as roundish masses about one-half