ection with exposure to cold or wet, with standing in a cold draft,
with blows on the udder with clubs, stones, horns, or feet, with injury
from a sharp or cold stone, or the projecting edge of a board or end of a
nail in the floor, with sudden and extreme changes of weather, with
overfeeding on rich albuminous feed like cotton seed, beans, or peas, with
indigestions, with sores on the teats, or with insufficient stripping of
the udder in milking. In the period of full milk the organ is so
susceptible that any serious disturbance of the general health is liable to
fall upon the udder.

_Symptoms._--The symptoms and mode of onset vary in different cases. When
following exposure there is usually a violent shivering fit, with cold
horns, ears, tail, and limbs, and general erection of the hair. This is
succeeded by a flush of heat (reaction) in which the horns, ears, and limbs
become unnaturally warm and the gland swells up and becomes firm and solid
in one, two, three, or all four quarters. There is hot dry muzzle, elevated
temperature, full, accelerated pulse, and excited breathing, impaired or
suspended appetite and rumination, with more or less costiveness,
suppression of urine, and a lessened yield of milk, which may be entirely
suppressed in the affected quarter.

In other cases the shivering escapes notice, the general disorder of the
system is little marked or comes on late, and the first observed sign of
illness is the firm swelling, heat, and tenderness of the bag. As the
inflammation increases and extends, the hot, tender udder causes the animal
to straddle with its hind limbs, and, when walking, to halt on the limb on
that side. If the cow lies down it is on the unaffected side. With the
increase in intensity and the extension of the inflammation the general
fever manifests itself more prominently. In some instances the connective
tissue beneath the skin and between the lobules of the gland is affected,
then the swelling is uniformly rounded and of nearly the same consistency,
pitting everywhere on pressure. In other cases it primarily attacks the
secreting tissue of the gland, then the swelling is more localized and
appears as hard, nodular masses in the interior of the gland. This last is
the usual form of inflammation occurring from infection entering by the
teats.

In all cases, but especially in the last-named form, the milk is suppressed
and replaced by a watery fluid colored with blood (sometimes deeply)