astringent, such as a weak solution of alum, then apply a thick coating of
pine tar; cover this with a layer of oakum or absorbent cotton; apply
another coat of tar over this, and then bandage closely and firmly. This
may remain without disturbance until the new growing wall becomes
sufficiently strong to sustain the pressure and weight of the animal. If,
however, at any time oozing or bad smell indicates that pus is forming
under this dressing, the bandage should be removed and the suppurating
surface freshly cleaned and dressed. This may have to be repeated every few
days and should be continued so long as there is any pus formation. If the
loss of hoof is owing to suppurative laminitis, the parts denuded of the
horny covering must be thoroughly cleansed and disinfected with carbolic
acid, lysol, or other antiseptic. Then apply a moderately thick layer of
absorbent cotton and over this apply the tar and bandage. After this the
antiseptic solution may be poured in daily at the top of the dressing. It
will thus soak in and saturate the dressing and inflamed tissue. It may
become necessary to remove all the dressing at daily or longer intervals to
give the parts a fresh cleaning, and then to reapply it.
FOUL IN FOOT (FOOT ROT).
A variety of causes may produce inflammation of the foot between the claws
or toes. It may be on account of overgrowth of the claws and inward
pressure, as in ingrowing nail of man, or it may be caused by the
irritation of stable filth by impaction and hardening of soil between the
claws, or by other foreign substances becoming wedged in, causing
inflammation and softening or ulceration of the skin in the interdigital
space. Under some conditions several cattle in the same herd become
affected, which has led some to think that the disease may be contagious.
Occurrences have been reported in which foot rot of cattle has appeared
within a short time among a large proportion of the cattle in a farming
district. This disease is most frequently seen in the hind feet, though all
four feet may become affected.
_Symptoms._--The animal is observed to limp. On examination of the foot we
discover heat and swelling above the hoof and of the soft parts between the
claws which frequently spreads the claws apart to a considerable extent, or
the inflammation may have advanced to softening and sloughing of the
interdigital membrane. If the disease is neglected at this stage, deep
abscesses may form and the pus burrow under the horny wall, or the joint
within the hoof may become inflamed and the articular attachments
destroyed, in which case the treatment will be difficult and recovery will
be very tedious.
_Treatment._--In the earlier stages of the disease, before pus burrows
beneath the horn, a thorough cleansing and an application of a
carbolic-acid solution--1 ounce to a pint of water--clean stabling,
and laxative food will usually remedy the evil. Compound solution of
cresol is an excellent remedy at this stage. It should be applied, in
its pure or undiluted state, to the suppurating and putrefying tissue
between the claws. It is best applied by means of a cotton swab on a
thin stick. Care must be taken to keep it from contact with the skin
about the coronary band or heels. If deep sloughing has taken place the
carbolic solution should be used, and a wad of oakum or cotton smeared
with pine tar should be secured firmly in the cleft. This can be done
by taking a strip of strong cloth, 2 inches wide, passing the middle
between the claws, then tying the ends after winding them in opposite
directions above the hoof. Sometimes warm poulticing with flaxseed meal
or bran is necessary to relieve excessive fever and pain. If the pus
burrows under the horn, its channel must be followed by paring away the
horn until the bottom is reached. The aftertreatment is the same as that
already recommended. If the joint becomes diseased an amputation of that
toe is the quickest and surest method to relieve the suffering of the
animal, and offers the best chance for an early recovery.
ULCERATION OF THE HEEL.
Occasionally we find ulcers at the junction of the hair with the hoof at
the heel, which present an elevated, raw, or ragged surface, and cause
considerable lameness. This is generally caused by a bruise of the fibrous
cushion of the back part of the foot. Subsequent sloughing or necrosis may
occur, or pus may form deep within the wall and gain an exit at the margin
of the heel. Sometimes, from no visible cause, large pieces of skin slough
from the heel and pastern. This condition is caused by an infection with
certain microorganisms (streptococci, necrosis bacilli) and may be
contagious.
_Treatment._--If there is a deep opening, inject carbolic solution once a
day until it closes. If the ulcer is only superficial, wash with carbolic
solution and apply a mixture of equal parts of blue vitriol and alum in dry
powder.
FISSURE OF THE WALL (SPLIT HOOF).
This is rarely seen among cattle. It may occur in weak walls, in heavily
bodied cattle, caused by stepping on an uneven surface, especially when the
point of the toe is grown out long. One may find the point of the toe
broken and the wall split almost up to the hair.
_Treatment._--The divided sections may be brought into approximation and
held in place by drilling a small hole from one side into and through the
other, commencing half an inch back of the fissure on each side; then drive
a light horseshoe nail through the hole and clinch it. Pare the injured
claw as short as it will bear.
INTERDIGITAL FIBROMA.
Hard, nodular, fibrous tumors sometimes grow in the cleft of the foot, and
cause inconvenience, lameness, absorption, or ulceration of the contiguous
parts.
_Treatment._--They should be dissected out and the wound dressed with
carbolic-acid lotion and pine tar once a day until healing is completed.
DEFORMITIES.
Deformities in the feet of cattle usually consist in overgrowth of horn,
generally from want of wear in animals which are stabled. The hoof may turn
inward, outward, or upward, and may give rise to lameness, inability to
walk, foul foot, etc. Bulls which are continually stabled and dairy cows
very frequently have misshapen feet from want of an occasional trimming,
and this deformity may eventually lead to permanent injury.
_Treatment._--Cut the superabundant growth of horn down with saw, knife, or
rasp, until the foot assumes its natural form.
PRICKS AND WOUNDS.
If an animal suffers with a penetrating wound from prick of fork or nail,
the orifice of the wound should be enlarged to permit a free discharge of
pus; then the foot should be soaked in a cresol compound solution (3 per
cent) in a tub, or a flaxseed poultice applied, changing it three times a
day until the fever has abated. The foot should be kept bandaged and
dressed with pine tar and oakum; the animal must also be kept on a clean
floor until the wound is closed and all or nearly all lameness has
disappeared.
If an animal is cut in the foot with barbed wire, piece of glass, or any
other substance, the wound, after proper cleansing, should be dressed with
carbolic-acid solution, 1 ounce of the acid to 20 of water. If any uneven
edges of horn, skin, or lacerated flesh project, trim them off, and in all
cases when it can be done a tarred bandage should be applied. This will
serve to sustain the cut surfaces in their place, exclude dirt, and protect
against flies, maggots, etc.
When the wound has extended into a joint, surgical treatment, which will
require the services of an educated veterinarian, may be necessary.
Occasionally an animal gets caught by the foot in a crevice and sustains
severe bruising, wrenching, or fracture of some part of the foot. In such
cases cold-water packs to the injured member are of service until the fever
and swelling disappear. Afterwards the animal should rest until the
usefulness of the foot is restored. Sometimes such an accident, causing
fracture, renders necessary plaster bandages or amputation.
DISEASES OF THE EYE AND ITS APPENDAGES.
By M. R. TRUMBOWER, D. V. S.
[Revised by Leonard Pearson, B. S., V. M. D.]
DESCRIPTION.
For the sake of gaining a clear comprehension of the diseases of the eye it
becomes necessary to review the anatomy of this important organ. The
essential organ of vision, or globe of the eye, will be first described,
then its receptacle or orbital cavity, the muscles that move it, the
protective membranes, or eyelids, the membrana nictitans, or accessory
eyelids, and, lastly, the lacrimal apparatus.
The globe or ball of the eye is almost spherical in form. On closer
inspection, however, it appears to be made up of two combined portions from
spheres of different sizes. The posterior portion, forming about
five-sixths of the ball, is a sphere of comparatively large size with a
small segment cut off it in front, and at this point there is applied to it
the anterior portion, which, being a segment of a smaller sphere, projects
at the front of the ball with a greater convexity than the posterior
portion.
The eyeball consists of concentrically arranged coats and of refracting
media inclosed in them. The coats are three in number, namely, (1) an
external protective tunic made up of the sclerotic and cornea; (2) a middle
vascular and pigmentary tunic, the choroid; (3) an internal nervous layer,
the retina. The sclerotic is the white, opaque part of the outer tunic, of
which it forms about the posterior five-sixths, being coextensive with the
larger sphere already mentioned. The cornea forms the remaining one-sixth
of the outer tunic, being coextensive with the segment of the smaller
sphere. It is distinguished from the sclerotic by being colorless and
transparent. The choroid coat will be recognized as the black layer lying
subjacent to the sclerotic. It does not line the cornea, but terminates
behind the line of junction of that coat with the sclerotic by a thickened
edge--the ciliary processes. At the line of junction of the sclerotic and
cornea the iris passes across the interior of the eye. This (which may be
viewed as a dependency of the choroid) is a muscular curtain perforated by
an aperture termed the pupil. The retina will be recognized as a delicate,
glassy layer, lining the greater part of the choroid.
The refracting media of the eye are three in number, namely (1) the aqueous
humor, a watery fluid inclosed in a chamber behind the cornea; (2) the
crystalline lens and its capsule, a transparent, soft solid of a biconvex
form, and placed behind the iris; (3) the vitreous humor, a transparent
material with a consistence like thin jelly, and occupying as much of the
interior of the eye as is subjacent to the choroid.
The sclerotic is a strong, opaque, fibrous membrane, which, in a great
measure, maintains the form of the eyeball and protects the more delicate
structures within it. Its interior portion, which is covered by the ocular
conjunctiva, is commonly known as the "white of the eye." In form it is
bell-shaped, and the optic nerve pierces it behind like a handle, the
perforation being a little to its inner side. In front, the rim of the bell
becomes continuous with the cornea. The outer surface of the membrane
receives the insertion of the muscles of the eyeball. The coat is thickest
over the posterior part of the eyeball, and is thinnest a little behind its
junction with the cornea.
The cornea is the anterior transparent portion of the outer coat of the
eyeball. It may be viewed as a part of the sclerotic specially modified to
permit the passage of light into the interior of the eye. Its outline is
elliptical, nearly circular, and its greatest diameter is transverse. At
its periphery it joins the sclerotic by continuity of tissue, and as the
edge of the cornea is slightly beveled and has the fibrous sclerotic
carried for a little distance forward on its outward surface, the cornea is
generally said to be fitted into the sclerotic like a watch glass into its
rim. The venous canal of Schlemm runs circularly around the eyeball at the
line of junction of the sclerotic and cornea. The anterior surface of the
cornea is exquisitely smooth, and is kept moist by the lacrimal secretions.
Its posterior surface forms the anterior boundary of the chamber in which
the aqueous humor is contained. The cornea is of uniform thickness and is
of a dense, almost horny, consistence. Save a few capillary loops of blood
vessels at its margin the cornea is without vessels. Its structure is
comprised of five distinct layers.
The aqueous humor occupies a chamber which is bounded in front by the
posterior surface of the cornea and behind by the capsule and suspensory
ligament of the lens and by the ends of the ciliary processes. It is across
this chamber that the iris extends. The aqueous humor is composed of water,
with a small proportion of common salt in solution.
The iris is a muscular, pigmented curtain extending across the interior of
the eye and having about its center an aperture termed the pupil. By
variations in the size of this aperture the amount of light transmitted to
the retina is regulated. It varies somewhat in color, but is most
frequently of a yellowish-brown tint. Its anterior face is bathed by the
aqueous humor. The greater part of the posterior surface is in contact with
the capsule of the lens and glides on it during the movements of the
curtain. The circumferential border is attached within the junction of the
sclerotic cornea. The inner border circumscribes the pupil, which varies in
outline according to its size. When much contracted the pupil is a very
elongated ellipse, the long axis of which is in the line joining the nasal
and temporal angles of the eyelids. It contains muscular tissue, which, by
contracting or relaxing, lessens or dilates the pupillary opening.
The choroid coat is a bell-shaped, dark membrane which lines the sclerotic.
Its outer surface has a shaggy appearance, caused by the tunica fusca,
which unites the two coats. Between the two the ciliary vessels and nerves
pass forward. Behind it is pierced by the optic nerve; in front it is
continued as the ciliary processes, which form, as it were, the rim of the
bell. The ciliary processes form a fringe around the slightly inverted rim
of the choroid.
The retina is the most delicate of the coats of the eyeball. It is formed
by the expansion of the optic nerve on the inner surface of the choroid,
and, like that coat, it is bell-shaped. Its inner surface is molded on the
vitreous humor. The nervous structures of the retina terminate at a wavy
line, the ora serrata, behind the ciliary processes. Ten distinct layers
are described as composing the thickness of the retina.
The lens is situated behind the pupil and is contained within a capsule of
its own.
The capsule is a close-fitting, firm, transparent membrane. The anterior
surface forms the posterior boundary of the cavity containing the aqueous
humor, and the iris in its movement glides on it. The posterior surface is
in contact with the vitreous humor.
The vitreous humor occupies four-fifths of the interior of the eyeball. It
is globular in form, with a depression in front for the lodgment of the
lens. It is colorless, transparent, and of a consistency like thin jelly.
It is enveloped by a delicate capsule--the hyaloid membrane--which is
connected in front with the suspensory ligament of the lens, and ends by
joining the capsule behind the lens.
The orbital cavity, at the side of the head, is circumscribed by a bony
margin; posteriorly, however, there are no bony walls, and the cavity is
often confounded with the depression above and behind the orbit--the
temporal fossa. A fibrous membrane completes this cavity and keeps it
distinct from the temporal fossa. This membrane--the ocular sheath or
periorbita--is attached posteriorly around the opening in the back part of
the orbital cavity (the orbital hiatus) and anteriorly to its inner face;
then it becomes prolonged beyond the margin to form the fibrous membrane of
the eyelids. When complete the orbital cavity has the form of a regular
hollow cone, open at its base and closed at the apex. The opening of this
cone is directed forward, downward, and outward. Independently of the globe
of the eye, this cavity lodges the muscles that move it, the membrana
nictitans, and the lacrimal gland.
The muscles of the eye are seven in number--one retractor, four straight,
and two oblique. The retractor oculi envelops the optic nerve between the
brain and the ball of the eye and becomes attached upon the external face
of the sclerotic tunic. When this muscle contracts, it draws the globe back
into the orbit, away from the light. The superior, inferior, external, and
internal recti or straight muscles are attached to the back part of the
orbital sheath and spread forward in four bundles over the globe of the
eye, where they are inserted by a fibrous expansion into the sclerotic at
the margin of the cornea. When they act singly, they turn the globe either
upward, downward, inward, or outward. The great oblique, by its action,
pivots the eye inward and upward in the orbit. The small oblique turns the
eye outward and downward.
The eyelids are two movable curtains, superior and inferior, which cover
and protect the eye in front. They are attached to the circumference of the
orbit and have a convex external face formed by the skin and a concave
internal face molded on the anterior surface of the eye and are lined by
the conjunctiva, which is reflected above and below on the eyeball. The
border of each lid is slightly beveled on the inner side and shows the
openings of the Meibomian glands. These glands secrete an unctuous fluid,
which is thrown out on the border of the lids, the function of which is to
facilitate their movements and enable them to retain the tears in the
ocular cavity. The eyelid is composed of a fibrous inner membrane ending in
a stiff arch near the border, a muscle to close the lid, another to open
it, the skin externally, and the conjunctival mucous membrane internally.
The border of each lid is covered and protected by long hairs to prevent
floating particles of matter in the atmosphere from gaining entrance to the
eye.
The membrana nictitans, which is also named the third eyelid, winking
eyelid, haw, etc., is placed at the inner angle of the eye, whence it
extends over the eyeball to relieve it from foreign bodies which may fall
upon it. It has for its framework a fibro-cartilage, irregular in shape,
thick, nearly prismatic at its base, and thin anteriorly where it is
covered by the conjunctiva; behind, it is loosely attached to a fatty
cushion.
The lacrimal gland is situated between the orbital process and the upper
part of the eyeball. It secretes the tears destined to lubricate the
anterior surface of the eye. This fluid escapes upon the organ at the outer
angle of the lids and is carried between them and the eyeball toward the
inner angle.
The caruncula lacrimalis is a small round body, frequently entirely or
partially black, situated in the inner angle of the eye, and is designed to
direct the tears toward the puncta lacrimalia.
The puncta lacrimalia are two little openings, situated one in each eyelid,
a short distance from the inner corner, which admit the tears into the
lacrimal ducts leading to the lacrimal canal, whence they are emptied into
the nasal passages.
CONJUNCTIVITIS (SIMPLE OPHTHALMIA).
This is an inflammation of the conjunctival mucous membrane of the eyeball
and lids; in severe cases the deeper coats of the eye are involved,
seriously complicating the attack.
_Causes._--It may result from a bruise of the eyelid; from the introduction
of foreign matters into the eye, as chaff, hayseed, dust, gnats, etc.; from
exposure to cold; poisonous or irritating vapors arising from filthiness of
stable. Dust, cinders, or sand blown into the eyes during transportation
frequently cause conjunctivitis.
_Symptoms._--A profuse flow of tears, closure of the eyelids from
intolerance of light, retraction of the eyeball and corresponding
protrusion of the haw, disinclination to move, diminution of milk
secretion, etc. On parting the lids the lining membrane is found injected
with an excess of blood, giving it a red and swollen appearance; the
sclerotic, or white of the eye, is bloodshot and the cornea may be cloudy.
If the disease advances, keratitis results, with its train of unfavorable
symptoms.
_Treatment._--Careful examination should be made to discover particles of
chaff, etc., which may have lodged in the eye, and upon the discovery of
such a cause prompt removal is indicated. This may be accomplished by
flushing the eye with warm water by means of a syringe, or, if the foreign
substance is adherent to the eyeball or lid, it may be scooped out with the
handle of a teaspoon or some other blunt instrument. To relieve the
congestion and local irritation, a wash composed of boracic acid in freshly
boiled water, 20 grains to the ounce, or acetate of zinc, 5 grains to the
ounce of pure soft water, may be used, to which may be added 20 drops of
laudanum. A few drops of this should be placed in the eye with a
camel's-hair pencil or soft feather three or four times daily. The animal
should be placed in a cool, darkened stable; then a cloth folded into
several thicknesses should be fastened to the horns in such manner as to
reach below the eyes. This should be kept wet with cold water during the
day and removed at night. If there is much fever and constitutional
disturbance, it becomes advisable to administer 1 pound of Epsom salt
dissolved in 1 quart of water.
INFECTIOUS CATARRHAL CONJUNCTIVITIS (SPECIFIC
OPHTHALMIA).
This generally appears in an enzootic or epizootic form and affects a
considerable number in the herd. It is distinctly a contagious disease and
may be brought into a previously healthy herd by one infected animal. It
may continue in a herd for a season or for several years, affecting all
newly purchased animals. It is seldom seen in the winter months. It affects
old and young animals alike.
_Symptoms._--This form of catarrh conjunctivitis is characterized chiefly
by a mucopurulent discharge from the eyes, an intense degree of
inflammation of the mucous membrane, accompanied with swelling of the
eyelids and an early opacity of the cornea. The flow of tears is mixed with
pus, sometimes streaked with blood, and the skin of the face is kept moist
and soiled. The eyes are kept continually closed. The implication of the
cornea in the disease frequently blinds the animal for a time, and
occasionally suppurative keratitis, ulcers of the cornea, or staphyloma
supervene. The attack is marked from the onset by fever, partial loss of
appetite, partial loss of milk, suspended rumination, and separation from
the herd.
_Treatment._--The animal should be housed in a cool, dark stable, supplied
with plenty of fresh water to drink and soft, succulent feed. Administer 1
pound of Epsom salt--if a very large animal, use 1-1/2 pounds--dissolved in
2 or 3 pints of water. For an eyewash, take boracic acid, 1 dram, and pour
4 ounces of boiling water over it. Use this as often as is convenient,
applying it directly to the eye. In the majority of cases improvement
becomes manifest in a few days, and the eye becomes clear and free from
inflammation in 10 days or 2 weeks. Where the disease develops ulceration
of the cornea, or well-marked, deep-seated keratitis, the treatment
recommended for those conditions should be adopted.
_Prevention._--Whenever this affection appears in a herd all the unaffected
animals should be moved to fields which possess a different character of
soil and feed. The water should also be changed, especially if they have
been obtaining it from a stagnant pond.
KERATITIS (CORNEITIS).
This is an inflammation of the cornea proper, although the sclerotic at the
corneal border becomes involved to some extent. It may be divided into
diffuse and suppurative.