464 DISEASES OF THE HORSE, 
The bites of insects often produce a papular eruption, but in many 
such cases the swelling extends wider into a buttonlike elevation, 
one-half to an inch in diameter. The same remarks apply to the 
effects of the poison ivy and poison sumac. 
Treatment.—In papular eruption first remove the cause, then apply 
the same general remedies as for simple congestion. In the more 
inveterate cases use a lotion of one-half ounce sulphid of potassium 
in 2 quarts of water, to which a little Castile soap has been added, or 
use a wash with one-half ounce oil of tar, 2 ounces Castile soap, and 
20 ounces water. 
INFLAMMATION WITH BLISTERS, OR ECZEMA. 
In this the skin is congested, thickened, warm (white skins are red- 
dened), and shows a thick crop of little blisters formed by effusions 
of a straw-colored fluid between the true skin and the cuticle. The 
blisters may be of any size from a millet seed to a pea, and often 
crack open and allow the escape of the fluid; which concretes as a 
slightly yellowish scab or crust around the roots of the hairs. This 
exudation and the incrustation are especially common where the hairs 
are long, thick, and numerous, as in the region of the pastern of 
heavy draft horses. The term eczema is now applied very generally 
to eruptions of all kinds that depend on internal disorders or consti- 
tutional conditions and that tend to recurrences and inveteracy. 
Eczema may appear on any part of the body, but in horses it is espe- 
cially common on the heels and the lower parts of the limbs, and 
less frequently on the neck, shoulder, and abdomen. The limbs ap- 
pear to be especially liable because of their dependent position, all 
blood having to return from them against the action of gravity and 
congestions and swellings being common, because of the abundance 
of blood vessels in this part of the skin and because of the frequent 
contact with the irritant dung and urine and their ammoniacal emana- 
tions. The legs further suffer from contact with wet and mud when 
at work, from snow and ice, from drafts of cold air on the wet limbs, 
from washing with caustic soaps, or from the relaxing effects of a 
too deep and abundant litter. Among other causes may be named 
indigestion and the presence of irritant matters in the blood and 
sweat, the result of patent medicated feeds and condition powders 
(aromatics, stimulants), green food, new hay, new oats, buckwheat, 
wheat, maize, diseased potatoes, smut, or ergot in grains, decompos- 
ing green feed, brewers’ grains, or kitchen garbage. The excite- 
ment in the skin, caused by shedding the coat, lack of grooming, hot 
weather, hot, boiled, or steamed feed conduces to the eruption. 
Lastly, any sudden change of feed may induce it. 
The blisters may in part go on to suppuration so that vesicles and 
pustules often appear on the same patch, and, when raw from rub- 
