affected with this disease. The natural method of entrance into the body is
through the bite of the cattle tick. The disease may be transmitted by
inoculating blood containing the parasite into a susceptible animal.

There are two forms of the disease, the _acute_ and _chronic_.

_The symptoms of the acute form_ of the disease are a high fever,
depression, loss of appetite, diarrhoea, dark or bloody urine, staggering
gait and delirium. Death may occur within a few days from the time the
first symptoms are manifested.

_The symptoms of the chronic form_ of the disease resemble the acute form,
but are more mild. The animal is unthrifty and loses flesh rapidly. The
bloodless condition of the body is manifested by the pale, visible mucous
membrane. Death seldom occurs.

[Illustration: FIG. 122.--Blood-cells with _Piroplasma bigeminum_ in them.]

The most characteristic _diseased changes_ found on post-mortem examination
occur in the liver and spleen. The liver is enlarged, and a yellowish,
mahogany-brown color. The gallbladder is filled with a very thick bile. The
spleen may be several times the normal size and dark colored. When it is
cut into, the pulpy tissue may resemble thick, dark blood. The kidneys are
pale and the bladder may contain dark or reddish-colored urine.

In the northern States and outside of the quarantined area, the direct or
indirect exposure of the affected cattle to southern cattle, and the
presence of the cattle tick, _Margarophus annulatus_, are sufficient
evidence to confirm the diagnosis of this disease.