unds, ulcerous
sores, and scabs. The intense itching will always suggest this parasite,
and the discovery of the acarus will identify the disease. The treatment
is the same as for the _Sarcoptes_, but may be confined to the legs and
the parts with which they come in contact.

PARASITE: _Dermanyssus gallinae, or chicken acari._ MALADY: _Poultry
acariasis._--This is a large-sized acarus, though usually miscalled "hen
louse," and the disease "poultry lousiness." The mite (Pl. XXXIX, fig.
4) lives in droppings and in crevices of chicken houses, but temporarily
passes on to the skin of man and of the horse and other quadrupeds, when
occasion serves. It causes much irritation, with the eruption of papules
or vesicles and the formation of sores and scabs. The examination of the
skin is usually fruitless, as the attacks are mostly made at night and
the effects only may be seen during the day. The proximity of hen manure
swarming with the acari explains the trouble, and the removal of this
and a white-washing with quicklime, with or without chlorid of lime,
will prevent future attacks. The skin may still require bland ointments
or lotions, as for congestion.

PARASITE: _Larva of a Trombidium, Leptus americanus, or harvest bug,
misnamed jigger (chigoe)._ MALADY: _Autumn mange._--This parasite is a
brick-red acarus, visible to the naked eye on a dark ground, and living
on green vegetation in many localities. It attacks man, and the horse,
ox, dog, etc., burrowing under the skin and giving rise to small papules
and intolerable irritation. This continues for two or three days only
from a single invasion, but will last until cold weather sets in if
there is a fresh invasion daily. Horses at pasture suffer mainly on the
lower part of the face. If kept indoors the disease will disappear, or
if left at pasture a weak tar water or solution of tobacco may be
applied to the face.

[Illustration: PLATE XXXIX.

MITES THAT INFEST THE HORSE.]

TICKS.

The wood ticks are familiar to inhabitants of uncultivated lands, and
prove troublesome parasites to man and beast alike. The tick lives on
bushes, and attaches itself to the mammal only to secure a feast of
blood, for when gorged it drops off to sleep off its debauch on the
soil. The tick produces great irritation by boring into the skin with
its armed proboscis. If pulled out, the head and thorax are often left
in the skin. They may be covered with oil to shut out the air from their
b