d may be either a direct or an
indirect one. The former consists in excluding all cattle, horses, and
mules from pastures until all the ticks have died from starvation. The
latter consists in permitting the cattle and other animals to continue on
the infested pasture and treating them at regular intervals with agents
destructive to ticks and thus preventing engorged females from dropping and
reinfesting the pasture. The larvae on the pasture, or those which hatch
from eggs laid by females already there, will all eventually meet death.
Such of these as get upon the cattle from time to time will be destroyed by
the treatment, while those which fail to find a host will starve in the
pasture.

Animals may be freed of ticks in two ways. They may be treated with an
agent that will destroy all the ticks present, or they may be rotated at
proper intervals on tick-free fields until all the ticks have dropped. The
method most generally used is dipping the cattle in a solution of arsenic.
The pasture-rotation method is not only more complicated, but the necessary
tick-free fields are seldom available.

DIPPING.

The dipping vat is the best and cheapest means of applying the
tick-destroying solution. The great advantage of dipping over spraying
and applying remedies by hand lies in the fact that thoroughness of the
treatment is practically assured.

When eradication is undertaken, all the cattle, and also the horses and
mules if they harbor ticks, are treated regularly every two weeks during
the part of the year that the temperature is favorable to treatment, until
the ticks have disappeared. The purpose of the treatment is to destroy all
ticks that get on the animals before they have had a chance to mature and
drop, thus preventing them from reinfesting the pasture, farm, or range. If
the treatment used were absolutely effective in destroying each and every
tick on the animals treated there would be no renewal of the infestation
after the treatment is begun. The cattle would act simply as collectors of
ticks which would be destroyed regularly by the treatment applied every two
weeks. It is probable, however, that in most instances, either because of
the lack of efficiency of the dip or imperfect application, or because of
failure to dip all cattle systematically, some ticks escape treatment and
reproduce, thus prolonging the time that otherwise would be required for
eradication.

If ticks apparently disappear from the cattl