layer of the skin and of the investing cuticular layer. They are mostly
seen in young horses, about the lips, eyelids, cheeks, ears, beneath the
belly, and on the sheath, but may develop anywhere. The smaller ones may
be clipped off with scissors and the raw surface cauterized with
bluestone. The larger may be sliced off with a sharp knife, or if with a
narrow neck they may be twisted off and then cauterized. If very
vascular they may be strangled by a wax thread or cord tied around their
necks, at least three turns being made around and the ends being fixed
by passing them beneath the last preceding turn of the cord, so that
they can be tightened day by day as they slacken by shrinkage of the
tissues. If the neck is too broad it may be transfixed several times
with a double-threaded needle and then be tied in sections. Very broad
warts that can not be treated in this way may be burned down with a
soldering bolt at a red heat to beneath the surface of the skin, and any
subsequent tendency to overgrowth kept down by bluestone.
BLACK PIGMENT TUMORS, OR MELANOSIS.
These are common in gray and in white horses on the naturally black
parts of the skin at the roots of the tail, around the anus, vulva,
udder, sheath, eyelids, and lips. They are readily recognized by their
inky-black color, which extends throughout the whole mass. They may
appear as simple, pealike masses, or as multiple tumors aggregating many
pounds, especially around the tail. In the horse these are usually
simple tumors, and may be removed with the knife. In exceptional cases
they prove cancerous, as they usually are in man.
EPITHELIAL CANCER, OR EPITHELIOMA.
This sometimes occurs on the lips at the angle of the mouth and
elsewhere in the horse. It begins as a small, wartlike tumor, which
grows slowly at first, but finally bursts open, ulcerates, and extends
laterally and deeply in the skin and other tissues, destroying them as
it advances (rodent ulcer). It is made up of a fibrous framework and
numerous round, ovoid, or cylindrical cavities, lined with masses of
epithelial cells, which may be squeezed out as a fetid, caseous
material. Early and thorough removal with the knife is the most
successful treatment.
VEGETABLE PARASITES OF THE SKIN.
(Pl. XXXVIII, figs. 2, 3, 4.)
PARASITE: _Trichophyton tonsurans._ MALADY: _Tinea tonsurans, or
circinate ringworm._--This is especially common in young horses coming
into training and work, in low-conditioned colts in winter and spring
after confinement indoors, during molting, in lymphatic rather than
nervous subjects, and at the same time in several animals that have
herded together. The disease is common to man, and among the domestic
animals to horse, ox, goat, dog, cat, and in rare instances to sheep and
swine. Hence it is common to find animals of different species and their
attendants suffering at once, the diseases having been propagated from
one to the other.
_Symptoms._--In the horse the symptoms are the formation of a circular,
scurfy patch where the fungus has established itself, the hairs of the
affected spot being erect, bristly, twisted, broken, or split up and
dropping off. Later the spot first affected has become entirely bald,
and a circular row of hairs around this are erect, bristly, broken, and
split. These in turn are shed and a new row outside passes through the
same process, so that the extension is made in more or less circular
outline. The central bald spot, covered with a grayish scurf and
surrounded by a circle of broken and split hairs, is characteristic. If
the scurf and diseased hairs are treated with caustic-potash solution
and put under the microscope, the natural cells of the cuticle and hair
will be seen to have become transparent, while the groups of spherical
cells and branching filaments of the fungus stand out prominently in the
substance of both, dark and unchanged. The eruption usually appears on
the back, loins, croup, chest, and head. It tends to spontaneous
recovery in a month or two, leaving for a time a dappled coat from the
spots of short, light-colored hair of the new growth.
The most effective way of reaching the parasite in the hair follicles is
to extract the hairs individually, but in the horse the mere shaving of
the affected part is usually enough. It may then be painted with
tincture of iodin twice a day for two weeks. Germs about the stable may
be covered up or destroyed by a whitewash of freshly burned quicklime,
the harness, brushes, etc., may be washed with caustic soda, and then
smeared with a solution of corrosive sublimate one-half dram and water 1
pint. The clothing may be boiled and dried.
PARASITE: _Achorion schoenleini._ MALADY: _Favus, or honeycomb
ringworm._--Megnin and Goyau, who describe this in the horse, say that
it loses its characteristic honeycomb or cup-shaped appearance, and
forms only a series of closely aggregated, dry, yellowish crusts the
size of hemp seed on the trunk, shoulders, flanks, or thighs. They are
accompanied by severe itching, especially at night. The cryptogam,
formed of spherical cells with a few filaments only, grows in the hair
follicles and on the cuticle, and thus a crust often forms around the
root of a hair. Like the other cryptogams, their color, as seen under
the microscope, is unaffected by acetic acid, alcohol, ether, or oil of
turpentine, while the cells are turned bluish by iodin. For treatment,
remove the hair and apply tincture of iodin or corrosive sublimate
lotion, as advised under the last paragraph.
PARASITE: _Microsporon furfur._ MALADY: _Parasitic pityriasis._--This
attacks the horse's head where the harness presses, and leads to
dropping of the hair, leaving bald patches covered with a branlike
scurf, without any eruption, heat, tenderness, swelling, or rigidity of
the skin. A lotion of carbolic acid 1 dram and water 2-1/2 ounces is
usually applied to effect a cure.
ANIMAL PARASITES OF THE SKIN.[6]
ACARIASIS, OR MANGE.
This affection is due to the irritation of the skin caused by the
presence of nearly microscopic acari, or mites. The disease varies,
however, according to the species of acarus which infests the skin, so
that we must treat of several different kinds of acariasis.
PARASITE: _Sarcoptes scabiei equi._ MALADY: _Sarcoptic acariasis._--This
is the special _Sarcoptes_ of the horse, but under favorable conditions
it can be transmitted to ass and mule, and even to man, and may live
indefinitely on the human skin. The mite (Pl. XXXIX, fig. 1) is nearly
microscopical, but may be detected with a magnifying lens among moving
scurf taken from the infected skin. Like all _Sarcoptes_, it burrows
little galleries in and beneath the scurf skin, where it hides and lays
its eggs and where its young are hatched. It is therefore often
difficult to find the parasite on the surface, unless the skin has been
heated by a temporary exposure to the sun or in a warm room. The mite
may be detected more readily by placing scrapings on black cardboard
and warming, or better by macerating scabs or scrapings in a solution of
caustic soda or potash and then examining them microscopically. Like
other acari, this is wonderfully prolific, a new generation of fifteen
individuals being possible every fifteen days, so that in three months
the offspring of a single pair may produce generations aggregating
1,500,000 young. The _Sarcoptes_ have less vitality than the
nonburrowing acari, as they die in an hour when kept apart from the skin
in dry air at a heat of 145 deg. F. They live 12 to 14 days apart from the
skin in the damp air of a stable. On a piece of damp hide they lived
till the twenty-fourth day, when they began to die, and all were dead on
the twenty-eighth.
_Symptoms._--The symptoms are an incessant, intolerable, and increasing
itching of some part of the skin (head, mane, tail, back, etc.), the
horse inclining himself toward the hand that scratches him, and moving
his lips as if himself scratching. The hairs may be broken and rubbed
off, but the part is never entirely bald, as in ringworm, and there may
be papules or any kind of eruption or open sores from the energy of the
scratching. Scabs of any thickness may form, but the special features
are the intense itching and the presence of the acarus.
_Treatment_ consists in the removal of the scabs by soapsuds, and, if
necessary, a brush and the thorough application of tobacco 1-1/2 ounces
and water 2 pints, prepared by boiling. This may be applied more than
once, and should always be repeated after 15 days, to destroy the new
brood that may have been hatched in the interval. All harness and stable
utensils should be similarly treated; blankets and rubbers may be
boiled, and the stalls should be covered with a whitewash of quicklime,
containing one-fourth pound of chlorid of lime to the gallon.
When there are too many animals to treat by means of hand dressings, the
lime-and-sulphur dip or the tobacco dip may be used and are very
effective, though the cresol dips are fairly effective. These dips may
be purchased and made up in the dilution called for on the container.
The affected animals may be dipped when the number warrants it and
facilities are available; otherwise the dips may be applied with a swab
or a spray pump. Directions for constructing a dipping vat may be
obtained from the United States Department of Agriculture on
application. Any treatment used should be repeated in the course of 10
to 14 days. If the stables are not disinfected, animals should be
removed after treatment and put in clean stables or on clean pasture for
at least a month to allow the mites in the infested stables to die.
Otherwise the disease may recur.
PARASITE: _Psoroptes equi_ (_Dermatocoptes equi_,
_Dermatodectes equi_). MALADY: _Psoroptic
acariasis._--Psoroptic mange is less common than sarcoptic
mange in horses, and as the parasite (Pl. XXXIX, fig. 3) only
bites the surface and lives among the crusts under the shelter of the
hair, it is very easily discovered. It reproduces itself with equal
rapidity and causes similar symptoms to those produced by the
_Sarcoptes_. The same treatment will suffice and is more promptly
effectual. The purifying of the stable must be more thorough, as the
_Psoroptes_ will survive twenty to thirty days in the moist atmosphere
of a stable, and may even revive after six or eight weeks when subjected
to moist warmth. Infested pastures will therefore prove dangerous to
horses for that length of time, and, with rubbing posts, etc, should not
be used.
PARASITE: _Chorioptes equi_ (_Symbiotes equi_, _Dermatophagus equi_,
_Chorioptes spathiferus_). MALADY: _Foot mange._--The acarus (Pl. XXXIX,
fig. 2) attacks the heels and lower parts of the legs, especially the
hind ones, and may be present for years without extending upon the body.
Like the _Psoroptes_; it lives on the surface, on the hairs, and among
the scabs. It gives rise to great itching, stamping, rubbing of the one
leg with the other, and the formation of papules, wounds, 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
breathing pores, or by touching them with a hot penknife they will be
impelled to let go their hold.
GRUBS IN SKIN.
PARASITE: _Hypoderma lineata_. MALADY: _Larvae_ (_grubs_) _under the
skin_.--The larvae of a fly (probably _Hypoderma lineata_, whose larvae in
the skin of cattle are commonly known as "warbles") are occasionally
found in little sacs beneath the skin of horses. The mature larva
escapes in early summer and develops into a fly. In districts where they
exist the grubs should be pressed out of the skin in the course of the
winter and destroyed.
LARVAE (GRUBS) ON THE SKIN, OR FLYBLOW.
The following flies, among others, deposit their eggs on open sores or
on wet, filthy parts of the skin, where their larvae or grubs give rise
to serious trouble: _Lucilia caesar_ (bluebottle), _Cochliomyia
macellaria_ (screwworm fly), _Musca vomitoria_ (meat fly), and
_Sarcophaga carnaria_ (flesh fly). To prevent their attacks, wet, filthy
hair should be removed and wounds kept clean and rendered antiseptic by
a lotion of carbolic acid 1 part, water 50 parts, or by a mixture of 1
ounce oil of tar in 20 ounces sweet oil, or by some other antiseptic. If
the grubs are already present they should be picked off and one of these
dressings freely applied.
FLIES.
A number of flies attack horses and suck their blood, producing great
annoyance and in some instances death. These insects not only suck the
blood, but also often instill an acid poison into the skin, and in
exceptional cases transfer infectious germs from animal to animal by
inoculation.
Various devices are resorted to to prevent the attacks, as to sponge the
skin with a decoction of walnut or elder leaves, of tobacco, to dust
with Persian insect powder, to keep a light blanket or fly net on the
horse, to close doors and windows with fine screens and destroy by
pyrethrum any flies that have gained admission, to remove all manure
heaps that would prove breeding places for flies, to keep the stalls
clean, deodorize by gypsum, and to spread in them trays of dry chlorid
of lime. For the poisoned bites apply ammonia, or a solution of 1 part
of carbolic acid in 20 parts of sweet oil or glycerin, or one-fourth
ounce bicarbonate of soda and 1 dram of carbolic acid in a quart of
water may be used.
A large number of fly repellents have been recommended, but most of them
must be applied daily in order to maintain the protective effect. Among
the things used are carbolic solutions, pine tar, oil of tar, fish oil,
laurel oil, oil of citronella, oil of sassafras, oil of camphor, and
cod-liver oil. These things must be used judiciously or they will result
in poisoning or removal of the hair from the animal in some instances.
Ten per cent oil of tar in Beaumont oil or in cottonseed oil was found
to be safe and efficacious by Graybill.
The use of the fly-maggot trap noted under stomach worms of the horse,
and of the various forms of the Hodge flytrap, is recommended.
FLEAS.
The flea of man and those of poultry, when numerous, will bite the horse
and give rise to rounded swellings on the skin. To dispose of them it is
needful to clear the surroundings of the grublike larvae as well as to
treat the victim. The soil may be sprinkled with quicklime, carbolic
acid, coal tar, or petroleum; the stalls may be deluged with boiling
water and afterwards painted with oil of turpentine and littered with
fresh pine sawdust, and all blankets should be boiled. The skin may be
sponged with a solution of 1 part carbolic acid in 50 parts of water.
Other animals should be kept free from fleas or kept away from the
vicinity of the stable.
The chigoe (_Pulex penetrans_) of the Gulf coast is still more
injurious, because it burrows under the surface and deposits its eggs to
be hatched out slowly with much irritation. The tumor formed by it
should be laid-open and the parasite extracted. If it bursts so that its
eggs escape into the wound, they may be destroyed by introducing
chloroform into the wound.
LICE, OR PEDICULI.
Two kinds of lice attack the horse, one of which is furnished with
narrow head and a proboscis for perforating the skin and sucking the
blood, and the other--the broad-headed kind--with strong mandibles, by
which it bites the skin only. The poor condition, itching, and loss of
hair should lead to suspicion, and a close examination will detect the
lice. They may be destroyed by rubbing the victim with sulphur
ointment, or with sulphuret of potassium 4 ounces, water 1 gallon, or
with tar water, or the skin may be sponged with benzine. The application
should be repeated a week later to destroy all lice hatched from the
nits in the interval. Buildings, clothes, etc., should be treated as for
fleas.
STINGS OF BEES, WASPS, AND HORNETS.
These are much more irritating than the bites of flies, partly because
the barbed sting is left in the wound and partly because of the quantity
and quality of the venom. When a swarm attacks an animal the result may
prove fatal.
_Treatment_ consists in the application of wet clay, or of a lotion of
soda or ammonia, or of carbolic acid, or permanganate of potash, 2
grains to the ounce; or of sugar of lead 2 drams, laudanum 1 ounce, and
water 1 pint. The embedded stings should be extracted with fine forceps
or even with the finger nails.
TARANTULA AND SCORPION.
The bite of the first and the sting of the second are poisonous, and may
be treated like other insect venom, by carbolated glycerin, or a strong
solution of ammonia, or permanganate of potash.
SNAKE BITES.
These are marked by the double incision caused by the two fangs, by the
excessive doughy (dark red) swelling around the wounds, and in bad cases
by the general symptoms of giddiness, weakness, and prostration. They
are best treated by enormous doses of alcohol, whisky, or brandy, or by
aqua ammonia very largely diluted in water, the object being to sustain
life until the poison shall have spent its power. As local treatment, if
the wound is in a limb, the latter may have a handkerchief or cord tied
around it above the injury and drawn tight by a stick twisted into it.
In this way absorption may be checked until the poison can be destroyed
by the application, of a hot iron or a piece of nitrate of silver or
other caustic. A poultice of tobacco leaves is a favorite remedy, and
may be used to soothe the sore after cauterization.
A treatment which has been highly recommended consists in prompt and
vigorous scarification at the site of puncture and rubbing crystals of
potassium permanganate into the wound.
BURNS AND SCALDS.
These subjects are discussed in the following chapter.
WOUNDS OF THE SKIN.
Wounds of the skin are fully discussed in the next chapter.
FOOTNOTES:
[3] An outbreak of quittor near Cheyenne, Wyo., which came under the
author's observation, was caused by the mud through which the horses had
to wade to reach the watering troughs. These troughs were furnished with
water by windmills, and the mudholes were caused by the waste water.
More than 50 cases developed inside of two months, or during September
and October. In these 50 cases all forms of the disease and all possible
complications were presented. During the rainy season at Leadville,
Colo., outbreaks of quittor are common, and the disease is so virulent
that it has long been known as the "Leadville foot rot." The soil being
rich in mineral matters is no doubt the cause of the outbreaks. In the
city of Montreal quittor is said to be very common in the early
springtime, when the streets are muddy from the melting snow and ice.
[4] Descazeaux has shown that the worms found in these summer sores are
probably larval forms of the stomach worms of the horse, _Habronema
megastoma_, _H. microstoma_, and _H. muscae_. Ransom has shown that the
larval stage of _H. muscae_ develops in the common housefly, the fly
becoming infested as a maggot in horse manure. Infestation with the
adult worms in the stomach of the horse (Pl. V, fig. 4) may take place
through the ingestion of such infested flies, or by the escape of the
larva from the proboscis of the fly as it feeds on the moist lips of the
horse. In view of this it may be surmised that summer sores may arise as
the result of flies so infested feeding on the moisture on the skin of
the horse. In some forms of summer sores along the abdomen there are
found immature stages of _Habronema_ which apparently have just escaped
from the egg and which are younger than some of the stages found in the
fly. In this case it is surmised that these embryos from the manure
enter the soiled skin of the horse, as it lies down on dirty bedding and
manure, and develop in the skin as they would ordinarily in the fly.
Descazeaux calls these summer sores cutaneous habronemiasis.
Preventive measures consist in the removal of the adult worms from the
stomach of the horse by the use of anthelmintics, the destruction of the
embryos in the manure, fly-control measures, and the use of clean
bedding.--M. C. HALL.
[5] Descazeaux recommends the application and injection of 2 to 3 per
cent trypanblue, though he states that the only truly efficacious
treatment is the early and complete ablation of the invaded tissue.--M.
C. H.
[6] Revised by M. C. Hall.
WOUNDS AND THEIR TREATMENT.
By CH. B. MICHENER, V. S.
[Revised by John R. Mohler, V. M. D., A. M.]
DESCRIPTION OF WOUNDS.
A wound is an injury to any part of the body involving a solution of
continuity or disruption of the affected parts and is caused by
violence, with or without laceration of the skin. In accordance with
this definition we have the following varieties of wounds: Incised,
punctured, contused, lacerated, gunshot, and poisoned. They may further
be classified as superficial, deep, or penetrating, and also as unclean,
if hair, dirt, or splinters of wood are present; as infected when
contaminated with germs, and as aseptic if the wound does not contain
germs.
An incised wound is a simple cut made with a sharp body, like a knife,
producing merely a division of the tissues. The duller the body the more
force is required, the more tissues destroyed, and a greater time will
be required for healing. In a cut wound the edges are even and definite,
while those of a lacerated wound are irregular and torn. Three
conditions are present as a result of an incised wound: (1) Pain, (2)
hemorrhage, (3) gaping of the wound. The first pain is due to the
crushing and tearing of the nerve fibers. In using a sharp knife and by
cutting quickly, the animal suffers less pain and healing occurs more
rapidly. The secondary pain is usually due to the action of the air and
inflammatory processes. When air is kept from the wound pain ceases soon
after the lesion is produced. Hemorrhage is absent only in wounds of
nonvascular tissues, as the cornea of the eye, the cartilage of joints,
and other similar structures. Bleeding may be from the arteries, veins,
or capillaries. In the last form of bleeding the blood oozes from the
part in drops. Hemorrhage from the veins is dark red and issues in a
steady stream without spurting. In arterial bleeding the blood is bright
red and spurts with each heart beat. This latter variety of hemorrhage
is the most dangerous, and should be stopped at once before attempting
any further treatment. Bleeding from small veins and capillaries ceases
in a short time spontaneously, while larger vessels, especially
arteries, require some form of treatment to cause complete stoppage of
the hemorrhage.
HEMOSTASIA.