The directions for dilution given by the manufacturer
should be carefully followed. As coal-tar-creosote dips do not mix well
with all kinds of water, they should be tested with the water to be used
for making the solution by mixing some of the dip in the proper proportions
with the water in a clean and clear-glass bottle or jar. If an oily layer
or mass of globules collects either at the top or the bottom of the mixture
after standing an hour, the dip is not suitable for use with that kind of
water. Imperfectly mixed coal-tar-creosote dips are liable to poison
animals even when not used in stronger solutions than that recommended by
the manufacturers, and are also likely to be inefficacious.

The lime-sulphur dip, which is highly efficacious as a mange remedy, is of
little value for destroying lice, especially blue lice. The arsenical dip
used in tick eradication is a good louse remedy, but its use is not
advisable on account of its poisonous nature, except under the supervision
of capable persons who know how to use it and what precautions to take.

[Illustration: FIG. 7.--Short-nosed blue louse (_Haematopinus
eurysternus_) of cattle. Enlarged. (From Bureau of Entomology.)]

[Illustration: FIG. 8.--Long-nosed bluelouse (_Linognathus
vituli_) of cattle. Enlarged. (From Bureau of Entomology.)]

[Illustration: FIG. 9.--Red louse (_Trichodectes scalaris_) of
cattle. Enlarged. (From Bureau of Entomology.)]

[Illustration: FIG. 10.--Egg of short-nosed blue louse
(_Haematopinus eurysternus_) attached to a hair. Enlarged. (From
Bureau of Entomology.)]

MANGE, ITCH, SCAB.[17]

Cattle are subject to four kinds of mange, of which common mange or
psoroptic mange is the most important.

PSOROPTIC MANGE.

Psoroptic mange of cattle is caused by small mites (fig. 11) which multiply
rapidly and are spread from diseased to healthy cattle by bodily contact,
or by pens, stables, railroad cars, etc., recently occupied by mangy
cattle. The mites attack the skin and cause it to become thickened and
covered with crusts and scabs, with a consequent loss of hair. Intense
itching accompanies the disease, and affected cattle are more or less
constantly rubbing and licking themselves. Psoroptic mange commences at the
root of the tail, or on the neck, or withers, and gradually extends over
the back up to the head, over the sides, and may finally affect nearly the
entire body except the legs. In serious cases the