the ground should be thoroughly wet with a four per cent water solution of
a cresol disinfectant and covered with lime.

_Vaccination_ of the exposed or susceptible animals should be practised. On
farms where the disease exists it may be necessary to vaccinate the young
animals (less than two years of age) once or twice every year in order to
prevent the disease. Medicinal treatment is unsatisfactory.

TEXAS OR TICK FEVER.--Tick fever is an infectious disease of cattle. It is
caused by an animal organism that is present in the blood, and is conveyed
from the animal that is host for the tick fever parasite to the
non-infected animal by a tick (Figs. 120 and 121).

[Illustration: FIG. 120.--Cattle tick (male).]

[Illustration: FIG. 121.--Cattle tick (female).]

Tick fever was introduced into the southern portion of the United States
through importation of cattle by the Spaniards. Previous to the
establishing of a definite quarantine line between the permanently infected
and the non-infected sections, heavy losses among northern cattle resulted
through driving and shipping southern cattle through the northern States.
The specific cause and the part taken by the tick in its distribution were
not discovered until 1889-'90. Smith recognized and discovered the specific
cause of the disease, and Kilborn and Salmon proved by a series of
experiments that the cattle tick was responsible for the transmission of
the disease from animal to animal.

_The specific cause_ of tick fever is a protozoan parasite, _Piroplasma
bigeminum_ (Fig. 122). It is present in the blood of cattle that are