aimed at, and this demands the most careful breeding, feeding, housing,
and general management, as indicated under "Causes." Much can also be
done by migration to a high, dry location, but for this and malarious
affections the improvement of the land by drainage and good cultivation
should be the final aim.
_Treatment_ is not satisfactory, but is largely the same as for common
internal ophthalmia. Some cases, like rheumatism, are benefited by
1-scruple doses of powdered colchicum and 2-dram doses of salicylate of
soda twice a day. In other cases, with marked hardness of the globe of
the eye from intraocular effusion, aseptic puncture of the eye, or even
the excision of a portion of the iris, has helped. During recovery a
course of tonics (2 drams oxid of iron, 10 grains nux vomica, and 1
ounce sulphate of soda daily) is desirable to invigorate the system and
help to ward off another attack. The vulgar resort to knocking out the
wolf teeth and cutting out the haw can only be condemned. The temporary
recovery would take place in one or two weeks, though no such thing had
been done, and the breaking of a small tooth, leaving its fang in the
jaw, only increases the irritation.
CATARACT.
The common result of internal ophthalmia, as of the recurrent type, may
be recognized as described under the first of these diseases. Its
offensive appearance may be obviated by extraction or depression of the
lens, but as the rays of light would no longer be properly refracted,
perfect vision would not be restored, and the animal would be liable to
prove an inveterate shyer. If perfect blindness continued by reason of
pressure on the nerve of sight, no shying would result.
PALSY OF THE NERVE OF SIGHT, OR AMAUROSIS.
_Causes._--The causes of this affection are tumors or other disease of
the brain implicating the roots of the optic nerve, injury to the nerve
between the brain and eye, and inflammation of the optic nerve within
the eye (retina), or undue pressure on the same from dropsical or
inflammatory effusion. It may also occur from overloaded stomach, from a
profuse bleeding, and even from the pressure of the gravid womb in
gestation.
_Symptoms._--The symptoms are wide dilatation of the pupils, so as to
expose fully the interior of the globe, the expansion remaining the
same in light and darkness. Ordinary eyes when brought to the light have
the pupils suddenly contract and then dilate and contract alternately
until they adapt themselves to the light. The horse does not swerve when
a feint to strike is made unless the hand causes a current of air. The
ears are held erect, turn quickly toward any noise, and the horse steps
high to avoid stumbling over objects which it can not see.
_Treatment_ is only useful when the disease is symptomatic of some
removable cause, like congested brain, overloaded stomach, or gravid
womb. When recovery does not follow the termination of these conditions,
apply a blister behind the ear and give one-half dram doses of nux
vomica daily.
TUMORS OF THE EYEBALL.
A variety of tumors attack the eyeball--dermoid, papillary, fatty,
cystic, and melanotic--but perhaps the most frequent in the horse is
encephaloid cancer. This may grow in or on the globe, the haw, the
eyelid, or the bones of the orbit, and can be remedied, if at all, only
by early and thorough excision. It may be distinguished from the less
dangerous tumors by its softness, friability, and great vascularity,
bleeding on the slightest touch, as well as by its anatomical structure.
STAPHYLOMA.
This consists in a bulging forward of the cornea at a given point by the
sacculate yielding and distention of its coats, and it may be either
transparent or opaque and vascular. In the last form the iris has become
adherent to the back of the cornea, and the whole structure is filled
with blood vessels. In the first form the bulging cornea is attenuated;
in the last it may be thickened. The best treatment is by excision of a
portion of the rise so as to relieve the intraocular pressure.
PARASITES IN THE EYE.
Acari in the eye have been incidentally alluded to under inflammation of
the lids.
_Filaria palpebralis_ is a white worm, one-half to 1 inch long, which
inhabits the lacrimal duct and the underside of the eyelids and haw in
the horse, producing a verminous conjunctivitis. The first step in
treatment in such cases is to remove the worm with forceps, then treat
as for external inflammation.
_Setaria equina_ is a delicate, white, silvery-looking worm, which I
have repeatedly found 2 inches in length (a length as great as 5 inches
has been reported). It invades the aqueous humor, where its constant
active movements make it an object of great interest, and it is
frequently exhibited as a "snake in the eye."[1] When present in the
eye it causes inflammation and has to be removed through an incision
made with the lancet in the upper border of the cornea close to the
sclerotic, the point of the instrument being directed slightly forward
to avoid injury to the iris. Then cold water or astringent antiseptic
lotions should be applied.
_Filaria conjunctivae_, resembling _Setaria equina_ very much in size and
general appearance, is another roundworm which has been found in the eye
of the horse.
The echinococcus, the cystic or larval stage of the echinococcus
tapeworm of the dog, has been found in the eye of the horse, and a
cysticercus is also reported.
FOOTNOTES:
[1] This worm is normally a parasite of the peritoneal cavity, and is
probably transmitted from one horse to another by some biting insect
which becomes infected by embryos in the blood.--M. C. HALL.
LAMENESS: ITS CAUSES AND TREATMENT.
BY A. LIAUTARD, M. D., V. M.,
_Formerly principal of the American Veterinary College, New York._
[Revised by John R. Mohler, A. M., V. M. D.]
It is as living, organized, locomotive machines that the horse, camel,
ox, and their burden-bearing companions are of practical value to man.
Hence the consideration of their usefulness and consequent value to
their human masters ultimately and naturally resolves itself into an
inquiry concerning the condition of that special portion of their
organism which controls their function of locomotion. This is especially
true in regard to the members of the equine family, the most numerous
and valuable of all the beasts of burden, and it naturally follows that
with the horse for a subject of discussion the special topic and leading
theme of inquiry, by an easy lapse, will become an inquest into the
condition and efficiency of his power for usefulness as a carrier or
traveler. There is a great deal of abstract interest in the study of
that endowment of the animal economy which enables its possessor to
change his place at will and convey himself whithersoever his needs or
his moods may incline him; how much greater, however, the interest that
attaches to the subject when it becomes a practical and economic
question and includes within its purview the various related topics
which belong to the domains of physiology, pathology, therapeutics, and
the entire round of scientific investigation into which it is finally
merged as a subject for medical and surgical consideration--in a word,
of actual disease and its treatment. It is not surprising that the
intricate and complicated apparatus of locomotion, with its symmetry and
harmony of movement and the perfection and beauty of its details and
adjuncts, by students of creative design and attentive observers or
nature and her marvelous contrivances and adaptations, should be
admiringly denominated a living machine.
Of all the animal tribe the horse, in a state of domesticity, is the
largest sharer with his master in his liability to the accidents and
dangers which are among the incidents of civilized life. From his
exposure to the missiles of war on the battlefield to his chance of
picking up a nail from the city pavement there is no hour when he is
not in danger of incurring injuries which for their repair may demand
the best skill of the veterinary practitioner. This is true not alone of
casualties which belong to the class of external and traumatic cases,
but includes as well those of a kind perhaps more numerous, which may
result in lesions of internal parts, frequently the most serious and
obscure of all in their nature and effects.
The horse is too important a factor in the practical details of human
life and fills too large a place in the business and pleasure of the
world to justify any indifference to his needs and physical comfort or
neglect in respect to the preservation of his peculiar powers for
usefulness. In entering somewhat largely, therefore, upon a review of
the subject, and treating in detail of the causes, the symptoms, the
progress, the treatment, the results, and the consequences of lameness
in the horse, we are performing a duty which needs no word of apology or
justification. The subject explains and justifies itself, and is its own
vindication and illustration, if any are needed.
The function of locomotion is performed by the action of two principal
systems of organs, known in anatomical and physiological terminology as
passive and active, the muscles performing the active and the bones the
passive portion of the movement. The necessary connection between the
cooperating parts of the organism is effected by means of a vital
contact by which the muscle is attached to the bone at certain
determinate points on the surface of the latter. These points of
attachment appear sometimes as an eminence, sometimes as a depression,
sometimes a border or an angle, or again as a mere roughness, but each
perfectly fulfilling its purpose, while the necessary motion is provided
for by the formation of the ends of the long bones into the requisite
articulations, joints, or hinges. Every motion is the product of the
contraction of one or more of the muscles, which, as it acts upon the
bony levers, gives rise to a movement of extension or flexion, abduction
or adduction, rotation or circumduction. The movement of abduction is
that which passes from and that of adduction that which passes toward
the median line, or the center of the body. The movements of flexion and
extension are too well understood to need defining. It is the
combination and rapid alterations of these movements which produce the
different postures and various gaits of the animal, and it is their
interruption and derangement, from whatever causes, which constitute the
pathological condition known as lameness.
A concise examination of the general anatomy of these organs, however,
must precede the consideration of the pathological questions pertaining
to the subject. A statement, such as we have just given, containing only
the briefest hint of matters which, though not necessarily in their
ultimate scientific minutiae, must be clearly comprehended in order to
acquire a symmetrical and satisfactory view of the theme as a practical
collation of facts to be remembered, analyzed, applied, and utilized.
It was the great Bacon who wrote: "The human body may be compared, from
its complex and delicate organization, to a musical instrument of the
most perfect construction, but exceedingly liable to derangement." In
its degree the remark is equally applicable to the equine body, and if
we would keep it in tune and profit by its harmonious action we must at
least acquaint ourselves with the relations of its parts and the mode of
their cooperation.
ANATOMY.
The bones, then, are the hard organs which in their connection and
totality constitute the skeleton of an animal (see Plate XXIII). They
are of various forms, three of which--the long, the flat, and the
small--are recognized in the extremities. These are more or less regular
in their form, but present upon their surfaces a variety of aspects,
exhibiting in turn, according to the requirement of each case, a
roughened or smooth surface, variously marked with grooves, crests,
eminences, and depressions, for the necessary muscular attachments, and,
as before mentioned, are connected by articulations and joints, of which
some are immovable and others movable.
The substance of the bone is composed of a mass of combined earthy and
animal matter surrounded by a fine, fibrous enveloping membrane (the
periosteum) which is intimately adherent to the external surface of the
bone, and is, in fact, the secreting membrane of the bony structure. The
bony tissue proper is of two consistencies, the external portion being
hard and "compact," and called by the latter term, while the internal,
known as the "spongy" or "areolar tissue," corresponds to the
descriptive terms. Those of the bones that possess this latter
consistency contain also, in their spongy portion, the medullary
substance known as marrow, which is deposited in large quantities in the
interior of the long bones, and especially where a central cavity
exists, called, for that reason, the medullary cavity. The nourishment
of the bones is effected by means of what is known as the nutrient
foramen, an opening established for the passage of the blood vessels
which convey the nourishment necessary to the interior of the organ.
Concerning the nourishment of the skeleton, there are other minutiae,
such as the venous arrangement and the classification of their arterial
vessels into several orders, which, though of interest as an abstract
study, are not of sufficient practical value to refer to here.
The active organs of locomotion, the muscles (see Plate XXIII), speaking
generally, form the fleshy covering of the external part of the skeleton
and surround the bones of the extremities. They vary greatly in shape
and size, being flat, triangular, long, short, or broad, and are
variously and capriciously named, some from their shape, some from their
situation, others from their use; and thus we have abductors and
adductors--the pyramidal, orbicular, the digastricus, the vastus, and so
on. Those which are under the control of the will, known as the
voluntary muscles, appear in the form of fleshy structures, red in
color, and with fibers of various degrees of fineness, and are composed
of fasciculi, or bundles of fibers, united by connective or cellular
tissue, each fasciculus being composed of smaller ones but united in a
similar manner to compose the larger formations, each of which is
enveloped by a structure of similar nature known as the sarcolemma. Many
of the muscles are united to the bones by the direct contact of their
fleshy fibers, but in other instances the body of the muscle is more or
less gradually transformed into a cordy or membranous structure known as
the tendon or sinew, and the attachment is made by the very short
fibrous threads through the medium of a long tendinous band, which,
passing from a single one to several others of the bones, effects its
object at a point far distant from its original attachment. In thus
carrying its action from one bone to another, or from one region of a
limb to another, these tendons must necessarily have smooth surfaces
over which to glide, either upon the bones themselves or formed at their
articulations, and this need is supplied by the secretion of the
synovial fluid, a yellowish, unctuous substance, furnished by a peculiar
tendinous synovial sac designed for the purpose.
Illustrations in point of the agency of the synovial fluid in assisting
the sliding movements of the tendons may be found under their various
forms at the shoulder joint, at the upper part of the bone of the arm,
at the posterior part of the knee joint, and also at the fetlocks, on
their posterior part.
As the tendons, whether singly or in company with others, pass over
these natural pulleys they are retained in place by strong, fibrous
bands or sheaths, which are by no means exempt from danger of injury, as
will be readily inferred from a consideration of their important special
use as supports and reenforcements of the tendons themselves, with which
they must necessarily share the stress of whatever force or strain is
brought to bear upon both or either.
We have referred to that special formation of the external surface of a
bone by which it is adapted to form a joint or articulation, either
movable or fixed, and a concise examination of the formation and
structure of the movable articulations will here be in place. These are
formed generally by the extremities of the long bones, or may exist on
the surfaces of the short ones. The points or regions where the contact
occurs are denominated the articular surface, which assumes from this
circumstance a considerable variety of aspect and form, being in one
case comparatively flat and another elevated; or as forming a protruding
head or knob, with a distinct convexity; and again presenting a
corresponding depression or cavity, accurately adapted to complete, by
their coaptation, the ball-and-socket joint. The articulation of the arm
and shoulder is an example of the first kind, while that of the hip with
the thigh bone is a perfect exhibition of the latter.
The structure whose office it is to retain the articulating surfaces in
place is the ligament. This is usually a white, fibrous, inelastic
tissue; sometimes, however, it is elastic in character and yellowish. In
some instances it is funicular shaped or corded, serving to bind more
firmly together the bones to which its extremities are attached; in
others it consists of a broad membrane, wholly or partially surrounding
the broad articulations, and calculated rather for the protection of the
cavity from intrusion by the air than for other security. This latter
form, known as capsular, is usually found in connection with joints
which possess a free and extended movement. The capsular and funicular
ligaments are sometimes associated, the capsular appearing as a
membranous sac wholly or partially inclosing the joint, the funicular,
here known as an interarticular ligament, occupying the interior, and
thus securing the union of the several bones more firmly and effectively
than would be possible for the capsular ligament unassisted.
The universal need which pertains to all mechanical contrivances of
motion has not been forgotten while providing for the perfect working of
the interesting piece of living machinery which performs the function of
locomotion, as we are contemplating it, and nature has consequently
provided for obviating the evils of attrition and friction and insuring
the easy play and smooth movement of its parts by the establishment of
the secretion of the synovia, the vital lubricant of which we have
before spoken, as a yellow, oily, or rather glairy secretion, which
performs the indispensable office of facilitating the play of the
tendons over the joints and certain given points of the bones. This
fluid is deposited in a containing sac, the lining (serous) membrane of
which forms the secreting organ. This membrane is of an excessively
sensitive nature, and while it lines the inner face of the ligaments,
both capsular and fascicular, it is attached only upon the edges of the
bones, without extending upon their length, or between the layers of
cartilage which lie between the bones and their articular surfaces.
Our object in thus partially and concisely reviewing the structure and
condition of the essential organs of locomotion has been rather to
outline a sketch which may serve as a reference chart of the general
features of the subject than to offer a minute description of the parts
referred to. Other points of interest will receive proper attention as
we proceed with the illustration of our subject and examine the matters
which it most concerns us to bring under consideration. The foundation
of facts which we have thus far prepared will be found sufficiently
broad, we trust, to include whatever may be necessary to insure a ready
comprehension of the essential matters which are to follow as our review
is carried forward to completion. What we have said touching these
elementary truths will probably be sufficient to facilitate a clear
understanding of the requirements essential to the perfection and
regularity which characterize the normal performance of the various
movements that result in the accomplishment of the action of locomotion.
So long as the bones, the muscles and their tendons, the joints with
their cartilages, their ligaments, and their synovial structure, the
nerves and the controlling influences which they exercise over all, with
the blood vessels which distribute to every part, however minute, the
vitalizing fluid which sustains the whole fabric in being and
activity--so long as these various constituents and adjuncts of animal
life preserve their normal exemption from disease, traumatism, and
pathological change, the function of locomotion will continue to be
performed with perfection and efficiency.
On the other hand, let any element of disease become implanted in one or
several of the parts destined for combined action, any change or
irregularity of form, dimensions, location, or action occur in any
portion of the apparatus--any obstruction or misdirection of vital power
take place, any interference with the order of the phenomena of normal
nature, any loss of harmony and lack of balance be betrayed--and we have
in the result the condition of lameness.
DEFINITION OF LAMENESS.
_Physiology._--Comprehensively and universally considered, then, the
term lameness signifies any irregularity or derangement of the function
of locomotion, irrespective of the cause which produced it or the degree
of its manifestation. However slightly or severely it may be exhibited,
it is all the same. The nicest observation may be demanded for its
detection, and it may need the most thoroughly trained powers of
discernment to identify and locate it, as in cases in which the animal
is said to be fainting, tender, or to go sore. On the contrary, the
patient may be so far affected as to refuse utterly to use an injured
leg, and under compulsory motion keep it raised from the ground, and
prefer to travel on three legs rather than to bear any portion of his
weight upon the afflicted member. In these two extremes, and in all the
intermediate degrees, the patient is simply lame--pathognomonic minutiae
being considered and settled in a place of their own.
This last condition of disabled function--lameness on three legs--and
many of the lower degrees of simple lameness are very easy of detection,
but the first, or mere tenderness or soreness, may be very difficult to
identify, and at times very serious results have followed from the
obscurity which has enveloped the early stages of the malady. For it may
easily occur that in the absence of the treatment which an early correct
diagnosis would have indicated, an insidious ailment may so take
advantage of the lapse of time as to root itself too deeply into the
economy to be subverted, and become transformed into a disabling chronic
case, or possibly one that is incurable and fatal. Hence the impolicy of
depreciating early symptoms because they are not accompanied with
distinct and pronounced characteristics, and from a lack of threatening
appearances inferring the absence of danger. The possibilities of an
ambush can never be safely ignored. An extra caution costs nothing, even
if wasted. The fulfillment of the first duty of a practitioner, when
introduced to a case, is not always an easy task, though it is too
frequently expected that the diagnosis, or "what is the matter" verdict,
will be reached by the quickest and surest kind of an "instantaneous
process" and a sure prognosis, or "how will it end," guessed at
instanter.