DISEASES OE THE SKIN AMONG- DOMESTICATED ANIMALS. 127 
and others describe, under different names, a rare skin disease of 
the horse, in which numerous nodules appear, which sooner or 
later suppurate and rupture, showing a varying quantity of 
worms in their interior. 
In the dog, Siedamgrotzky saw a pustular exanthem upon the 
external surface of the anterior and posterior limbs. The cause 
of this he found to be small embryonic round worms, which had 
manifestly wandered from the straw of the litter into the hair- 
sacks. / 
Similar observations have been made by Rivolta on the dog, 
and Pflug, Drnilly, and Semmer upon the horse. 
18.—H^ematopinus and Trichodectes. 
The Hoematojpini (Pediculi) are blood-suckers which cause a 
troublesome itching, and hence rubbing, scouring, and gnawing, 
which may lead to the formation of a dermatitis artificialis. 
Almost every variety of animal has its own species. Thus the 
domestic and the wild swine harbor H. urius sive suis; the horse, 
H. macrocephalus s. equi.; the cow, H. eurysternus and H. ten- 
uirostris; the goat, H. stenopsis; the dog, H. piliferus. 
The trichodectes do not suck the blood, but feed on the epi¬ 
dermis and gnaw the hairs with their forceps-like jaws. The dog 
has Tr. latus sive canis; the sheep, Tr. sphserocephalus; cattle, 
Tr. scalaris; the horse, Tr. pilosus; the goat, Tr. climax; the 
cat, Tr. subrostratus. 
Treatinent consists in the application of remedies that either 
prevent the access of the lice to air (closing up the breathing- 
holes), or poisons them. To the first belong the fatty oils, es¬ 
pecially rapidly-dying linseed oil, ashes, stone-dust, &c ; to the 
latter belong decoctum nicotianse, unguentum hydrargyri, (cattle 
are easily mercurialized !), sublimate solution (1:100), flores pyre- 
thri, semen sabadillae, semen stapliidis agriae, radix veratri, oleum 
anisi acthereum, (1:10 oil), benzine, petroleum, carbolic acid, (1: 
10 to 20), arsenical solutions (1:200), oleum cornu cervi. 
19.—Ixodes, Dermanysstjs, Pulex, Simulia, CEstrus, Ochromyia, 
Lucilia, Leptus. 
The ticks, (Ixodes), especially the females (Koch), occasionally 
bore into the skins of animals by means of their very complicated 
