ors with
broad bases. Their position may be such as to interfere with swallowing and
with breathing. In either case serious symptoms will soon appear.

The invasion of the bones of the jaws by actinomycosis must be regarded as
one of the most serious forms of the disease. (Pls. XXXIX, XL.) It may
start in the marrow of the bone and by a slow extension gradually undermine
the entire thickness of the bone itself. The growth may continue outward,
and after working its way through muscle and skin finally break through and
appear externally as stinking fungoid growths. The growth may at the same
time work its way inward and appear in the mouth. The disease may also
begin in the periosteum, or covering of the bone, and destroy the bone from
without inward.

Actinomycosis of the lungs is occasionally observed, and it is not
improbable that at times it has been mistaken for tuberculosis. The
actinomyces grains are, however, easily observed if the diseased tissue is
carefully examined. The changes in the lungs as they appear to the naked
eye vary considerably from case to case. Thus in one animal the lungs were
affected as in ordinary bronchopneumonia as to the location, extent, and
appearance of the disease process. The affected lobes had a dark-red flesh
appearance, with yellowish areas sprinkled in here and there. (See Pl. XLI,
figs. 1, 2.) These latter areas were the seat of multiplication of the
actinomyces fungus. In another case, of which only a small portion of the
lungs was sent to the laboratory, they were completely transformed into a
uniformly grayish mass, very soft and pulpy to the touch, and appearing
like very soft and moist dough. (Pl. XLI, fig. 3.) The actinomyces grains
were exceedingly abundant in this tissue, and appeared when the tissue was
incised as minute sulphur-yellow grains, densely sprinkled through the
tissue, which readily came away and adhered to the knife blade. In still
another case a portion of the lung tissue was converted into large, soft
masses from 1 to 3 inches in diameter, each partly inclosed in very dense
connective tissue. These soft, grayish-yellow masses likewise resembled
moist dough in their consistency, and the actinomyces grains, though
neither very distinct nor at all abundant, were easily fished out and
identified as such. A portion of this growth, which was as large as a
child's head, was converted into an abscess filled with creamy semiliquid
pus.

This case differed from t