attained, and urine or feces or both escape freely into the vagina. The
simple laceration of the anus is easily sewed up, but the ends of the
muscular fibers do not reunite and the control over the lower bowel is
never fully reacquired. The successful stitching up of the wound
communicating with the bladder or the rectum requires unusual skill and
care, and though I have succeeded in a case of the latter kind, I can
not advise the attempt by unprofessional persons.
BLOOD CLOTS IN THE WALLS OF THE VAGINA.
(See "Effusion of blood in the vaginal walls," p. 190.)
LAMINITIS, OR FOUNDER, FOLLOWING PARTURITION.
This sometimes follows on inflammation of the womb, as it frequently
does on disorder of the stomach. Its symptoms agree with those of the
common form of founder, and treatment need not differ.
INFLAMMATION OF THE WOMB AND PERITONEUM.
These may result from injuries sustained by the womb during or after
parturition, from exposure to cold or wet, or from the irritant
infective action of putrid products within the womb. Under the
inflammation the womb remains dilated and flaccid, and decomposition of
its secretions almost always occurs, so that the inflammation tends to
assume a putrid character and general septic infection is likely to
occur.
_Symptoms._--The symptoms are ushered in by shivering, staring coat,
small, rapid pulse, elevated temperature, accelerated breathing, loss of
appetite, with arched back, stiff movement of the body, looking back at
the flanks, and uneasy motions of the hind limbs, discharge from the
vulva of a liquid at first watery, reddish, or yellowish, and later it
may be whitish or glairy, and fetid or not in different cases.
Tenderness of the abdomen shown on pressure is especially
characteristic of cases affecting the peritoneum or lining of the belly,
and is more marked lower down. If the animal survives, the inflammation
tends to become chronic and attended by a whitish mucopurulent
discharge. If, on the contrary, it proves fatal, death is preceded by
extreme prostration and weakness from the general septic poisoning.
_Treatment._--In treatment the first thing to be sought is the removal
of all offensive and irritant matters from the womb through a caoutchouc
tube introduced into the womb, and into which a funnel is fitted. Warm
water should be passed until it comes away clear. To insure that all the
womb has been washed out, the oiled hand may be introduced to carry the
end of the tube into the two horns successively. When the offensive
contents have been thus removed, the womb should be injected with a
quart of water holding in solution 1 dram permanganate of potash, or, in
the absence of the latter, 2 teaspoonfuls of carbolic acid, twice daily.
Fomentation of the abdomen, or the application of a warm flaxseed
poultice, may greatly relieve. Acetanilid, in doses of half an ounce,
twice or thrice a day, or sulphate of quinia in doses of one-third
ounce, may be employed to reduce the fever. If the great prostration
indicates septic poisoning, large doses (one-half ounce) bisulphite of
soda, or salicylate of soda, or sulphate of quinin may be resorted to.
LEUCORRHEA.
This is a white, glutinous, chronic discharge, the result of a
continued, subacute inflammation of the mucous membrane of the womb.
Like the discharge of acute inflammation, it contains many forms of
bacteria, by some of which it is manifestly inoculable on the penis of
the stallion, producing ulcers and a specific, gonorrheal discharge.
_Treatment_ may consist in the internal use of tonics (sulphate of iron,
3 drams, daily) and the washing out of the womb, as described under the
last heading, followed by an astringent antiseptic injection (carbolic
acid, 2 teaspoonfuls; tannic acid, 1/2 dram; water, 1 quart). This may
be given two or three times a day.
DISEASES OF THE UDDER AND TEATS.
CONGESTION AND INFLAMMATION OF THE UDDER.
This is comparatively rare in the mare, though in some cases the udder
becomes painfully engorged before parturition, and a doughy swelling,
pitting on pressure, extends forward on the lower surface of the
abdomen. When this goes on to active inflammation, one or both of the
glands becomes enlarged, hot, tense, and painful; the milk is dried up
or replaced by a watery or reddish, serous fluid, which at times becomes
fetid; the animal walks lame, loses appetite, and shows general disorder
and fever. The condition may end in recovery, in abscess, induration,
or gangrene, and, in some cases, may lay the foundation for a tumor of
the gland.
_Treatment._--The treatment is simple so long as there is only
congestion. Active rubbing with lard or oil, or, better, camphorated
oil, and the frequent drawing off of the milk, by the foal or with the
hand, will usually bring about a rapid improvement. When active
inflammation is present, fomentation with warm water may be kept up for
an hour and followed by the application of the camphorated oil, to which
has been added some carbonate of soda and extract of belladonna. A dose
of laxative medicine (4 drams Barbados aloes) will be of service in
reducing fever, and one-half ounce saltpeter daily will serve a similar
end. In case the milk coagulates in the udder and can not be withdrawn,
or when the liquid becomes fetid, a solution of 20 grains carbonate of
soda and 10 drops carbolic acid dissolved in an ounce of water should be
injected into the teat. In doing this it must be noted that the mare has
three separate ducts opening on the summit of each teat and each must be
carefully injected. To draw off the fetid product it may be needful to
use a small milking tube, or spring teat dilator designed by the writer.
(Plate XIV, figs. 2 and 3.) When pus forms and points externally and can
not find a free escape by the teat, the spot where it fluctuates must be
opened freely with the knife and the cavity injected daily with the
carbolic-acid lotion. When the gland becomes hard and indolent, it may
be rubbed daily with iodin ointment 1 part, vaseline 6 parts.
TUMORS OF THE UDDER.
As the result of inflammation of the udder it may become the seat of an
indurated diseased growth, which may go on growing and seriously
interfere with the movement of the hind limbs. If such swellings do not
give way in their early stages to treatment by iodin, the only resort is
to cut them out with a knife. As the gland is often implicated and has
to be removed, such mares can not in the future suckle their colts and
therefore should not be bred.
SORE TEATS, SCABS, CRACKS, WARTS.
By the act of sucking, especially in cold weather, the teats are subject
to abrasions, cracks, and scabs, and as the result of such irritation,
or independently, warts sometimes grow and prove troublesome. The warts
should be clipped off with sharp scissors and their roots burned with a
solid pencil of lunar caustic. This is best done before parturition to
secure healing before suckling begins. For sore teats use an ointment of
vaseline 1 ounce, balsam of tolu 5 grains, and sulphate of zinc 5
grains.
DISEASES OF THE NERVOUS SYSTEM.
By M. R. TRUMBOWER, V. S.
[Revised by John R. Mohler, A. M., V. M. D.]
ANATOMY AND PHYSIOLOGY OF THE BRAIN AND NERVOUS SYSTEM.
(Pl. XIX.)
The nervous system may be regarded as consisting of two sets of organs,
peripheral and central, the function of one being to establish a
communication between the centers and the different parts of the body,
and that of the other to generate nervous force. The whole may be
arranged under two divisions: First, the cerebrospinal system; second,
the sympathetic or ganglionic system. Each is possessed of its own
central and peripheral organs.
In the first, the center is made up of two portions--one large and
expanded (the brain) placed in the cranial cavity; the other elongated
(spinal cord), continuous with the brain, and lodged in the canal of the
vertebral column. The peripheral portion of this system consists of the
cerebrospinal nerves, which leave the axis in symmetrical pairs and are
distributed to the skin, the voluntary muscles, and the organs.
In the second, the central organ consists of a chain of ganglia,
connected by nerve cords, which extends on each side of the spine from
the head to the rump. The nerves of this system are distributed to the
involuntary muscles, mucous membrane, viscera, and blood vessels.
The two systems have free intercommunication, ganglia being at the
junctions.
Two substances, distinguishable by their color, namely, the white or
medullary and the gray or cortical substance, enter into the formation
of nervous matter. Both are soft, fragile, and easily injured, in
consequence of which the principal nervous centers are well protected by
bony coverings. The nervous substances present two distinct forms--nerve
fibers and nerve cells. An aggregation of nerve cells constitutes a
nerve ganglion.
The nerve fibers represent a conducting apparatus and serve to place the
central nervous organs in connection with peripheral end organs. The
nerve cells, however, besides transmitting impulses, act as
physiological centers for automatic, or reflex, movements, and also for
the sensory, perceptive, trophic, and secretory functions. A nerve
consists of a bundle of tubular fibers, held together by a dense
areolar tissue, and inclosed in a membranous sheath--the neurilemma.
Nerve fibers possess no elasticity, but are very strong. Divided nerves
do not retract.
Nerves are thrown into a state of excitement when stimulated, and are,
therefore, said to possess excitable or irritable properties. The
stimuli may be applied to, or may act upon, any part of the nerve.
Nerves may be paralyzed by continuous pressure being applied. When the
nerves divide into branches, there is never any splitting up of their
ultimate fibers, nor yet is there ever any coalescing of them; they
retain their individuality from their source to their termination.
Nerves which convey impressions to the centers are termed sensory, or
centripetal, and those which transmit stimulus from the centers to
organs of motion are termed motor, or centrifugal. The function of the
nervous system may, therefore, be defined in the simplest terms, as
follows: It is intended to associate the different parts of the body in
such a manner that stimulus applied to one organ may excite or depress
the activity of another.
The brain is that portion of the cerebrospinal axis within the cranium,
which may be divided into four parts--the medulla oblongata, the
cerebellum, the pons Varolii, and the cerebrum--and it is covered by
three membranes, called the meninges. The outer of these membranes, the
dura mater, is a thick, white, fibrous membrane which lines the cavity
of the cranium, forming the internal periosteum of the bones; it is
continuous with the spinal cord to the extremity of the canal. The
second, the arachnoid, is a delicate serous membrane, and loosely
envelops the brain and spinal cord; it forms two layers, having between
them the arachnoid space which contains the cerebrospinal fluid, the use
of which is to protect the spinal cord and brain from pressure. The
third, or inner, the pia mater, is closely adherent to the entire
surface of the brain, but is much thinner and more vascular than when it
reaches the spinal cord, which it also envelops, and is continued to
form the sheaths of the spinal nerves.
The medulla oblongata is the prolongation of the spinal cord, extending
to the pons Varolii. This portion of the brain is very large in the
horse: it is pyramidal in shape, the narrowest part joining the cord.
The pons Varolii is the transverse projection on the base of the brain,
between the medulla oblongata and the peduncles of the cerebrum.
The cerebellum is lodged in the posterior part of the cranial cavity,
immediately above the medulla oblongata; it is globular or elliptical in
shape, the transverse diameter being greatest. The body of the
cerebellum is composed of gray matter externally and of white matter in
the center. The cerebellum has the function of co-ordinating movements;
that is, of so associating them as to cause them to accomplish a
definite purpose. Injuries to the cerebellum cause disturbances of the
equilibrium but do not interfere with the will power or intelligence.
The cerebrum, or brain proper, occupies the anterior portion of the
cranial cavity. It is ovoid in shape, with an irregular, flattened base,
and consists of lateral halves or hemispheres. The greater part of the
cerebrum is composed of white matter. The hemispheres of the cerebrum
are usually said to be the seat of all psychical activities. Only when
they are intact are the process of feeling, thinking, and willing
possible. After they are destroyed the organism comes to be like a
complicated machine, and its activity is only the expression of the
internal and external stimuli which act upon it.
The spinal cord, or spinal marrow, is that part of the cerebrospinal
system which is contained in the spinal canal of the backbone, and
extends from the medulla oblongata to a short distance behind the loins.
It is an irregularly cylindrical structure, divided into two lateral,
symmetrical halves by fissures. The spinal cord terminates posteriorly
in a pointed extremity, which is continued by a mass of nerve
trunks--cauda equinae. A transverse section of the cord reveals that it
is composed of white matter externally and of gray matter internally.
The spinal cord does not fill the whole spinal canal. The latter
contains, besides, a large venous sinus, fatty matter, the membranes of
the cord, and the cerebrospinal fluid.
The spinal nerves, forty-two or forty-three in number, arise each by two
roots, a superior or sensory, and an inferior or motor. The nerves
originating from the brain are twenty-four in number, and arranged in
pairs, which are named first, second, third, etc., counting from before
backward. They also receive special names, according to their functions
or the parts to which they are distributed, viz:
1. Olfactory.
2. Optic.
3. Oculo-motor.
4. Pathetic.
5. Trifacial.
6. Abducens.
7. Facial.
8. Auditory.
9. Glossopharyngeal.
10. Pneumogastric.
11. Spinal accessory.
12. Hypoglossal.
Inflammation of the Brain and its Membranes (Encephalitis, Meningitis,
Cerebritis).
Inflammation may attack these membranes singly, or any one of the
anatomical divisions of the nerve matter, or it may invade the whole at
once. Practical experience, however, teaches us that primary
inflammation of the dura mater is of rare occurrence, except in direct
mechanical injuries to the head or diseases of the bones of the cranium.
Neither is the arachnoid often affected with acute inflammation, except
as a secondary result. The pia mater is most commonly the seat of
inflammation, acute and subacute, but from its intimate relation with
the surface of the brain the latter very soon becomes involved in the
morbid changes. Practically, we can not separate inflammation of the pia
mater from that of the brain proper. Inflammation may, however, exist in
the center of the great nerve masses--the cerebrum, cerebellum, pons
Varolii, or medulla at the base of the brain--without involving the
surface. When, therefore, inflammation invades the brain and its
enveloping membranes it is properly called encephalitis; when the
membranes alone are affected it is called meningitis, or the brain
substance alone cerebritis. Since all the conditions merge into one
another and can scarcely be recognized separately during the life of the
animal, they may here be considered together.
_Causes._--Exposure to extreme heat or cold, sudden and extreme changes
of temperature, excessive continued cerebral excitement, too much
nitrogenous feed, direct injuries to the brain, such as concussion, or
from fracture of the cranium, overexertion, sometimes as sequelae to
influenza, pyemia, poisons having a direct influence upon the encephalic
mass, extension of inflammation from neighboring structures, food
poisoning, tumors, parasites, metastatic abscesses, etc.
_Symptoms._--The diseases here grouped together are accompanied with a
variety of symptoms, almost none of which, however, are associated so
definitely with a special pathological process as to point unmistakably
to a given lesion. Usually the first symptoms indicate mental
excitement, and are followed by symptoms indicating depression. Acute
encephalitis may be ushered in by an increased sensibility to noises,
with more or less nervous excitability, contraction of the pupils of the
eyes, and a quick, hard pulse. In very acute attacks these symptoms,
however, are not always noted. This condition will soon be followed by
muscular twitchings, convulsive or spasmodic movements, eyes wide open
with shortness of sight. The animal becomes afraid to have his head
handled. Convulsions and delirium will develop, with inability of
muscular control, or stupor and coma may supervene. When the membranes
are greatly implicated, convulsions and delirium with violence may be
expected, but if the brain substances are principally affected stupor
and coma will be the prominent symptoms. In the former condition the
pulse will be quick and hard; in the latter, soft and depressed, with
often a dilatation of the pupils, and deep, slow, stertorous breathing.
The symptoms may follow one another in rapid succession, and the disease
approach a fatal termination within 12 hours. In subacute attacks the
symptoms are better defined, and the animal seldom dies before the third
day. Within three or four days gradual improvement may become manifest,
or cerebral softening with partial paralysis may occur. In all cases of
encephalitis there is a marked rise in temperature from the very onset
of the disease, with a tendency to increase until the most alarming
symptoms develop, succeeded by a decrease when coma becomes manifest.
The violence and character of the symptoms greatly depend upon the
extent and location of the structures involved. Thus, in some cases
there may be marked paralysis of certain muscles, while in others there
may be spasmodic rigidity of muscles in a certain region. Very rarely
the animal becomes extremely violent early in the attack, and by rearing
up, striking with the fore feet, or falling over, may do himself great
injury. Usually, however, the animal maintains the standing position,
propping himself against the manger or wall, until he falls from
inability of muscular control, or from unconsciousness. Occasionally, in
his delirium, he may go through a series of automatic movements, such as
trotting or walking, and, if loose in a stall, will move around
persistently in a circle. Early and persistent constipation of the
bowels is a marked symptom in nearly all acute affections of the brain;
retention of the urine, also, is frequently observed.
Following these symptoms there are depression, loss of power and
consciousness, lack of ability or desire to move, and usually fall of
temperature. At this stage the horse stands with legs propped, the head
hanging or resting on the manger, the eyes partly closed, and does not
respond when spoken to or when struck with a whip.
Chronic encephalitis or meningitis may succeed the acute stage, or may
be due to stable miasma, blood poison, narcotism, lead poisoning, etc.
This form may not be characterized in its initial stages by
excitability, quick and hard pulse, and high fever. The animal usually
appears at first stupid; eats slowly; the pupil of the eye does not
respond to light quickly; the animal often throws his head up or shakes
it as if suffering sudden twinges of pain. He is slow and sluggish in
his movements, or there may be partial paralysis of one limb, one side
of the face, neck, or body. These symptoms, with some variations, may be
present for several days and then subside, or the disease may pass into
the acute stage and terminate fatally. Chronic encephalitis may effect
an animal for ten days or two weeks without much variation in the
symptoms before the crisis is reached. If improvement commences, the
symptoms usually disappear in the reverse order to that in which they
developed, with the exception of the paralytic effects, which remain
intractable or permanent. Paralysis of certain sets of muscles is a very
common result of chronic, subacute, and acute encephalitis, and is due
to softening of the brain or to exudation into the cavities of the brain
or arachnoid space.
Softening and abscess of the brain are terminations of cerebritis. It
may also be due to an insufficient supply of blood as a result of
diseased cerebral arteries and of apoplexy. The symptoms are drowsiness,
vertigo, or attacks of giddiness, increased timidity, or fear of
familiar objects, paralysis of one limb, hemiplegia, imperfect control
of the limbs, and usually a weak, intermittent pulse. In some cases the
symptoms are analogous to those of apoplexy. The character of the
symptoms depends upon the seat of the softening or abscess within the
brain.
Cerebral sclerosis sometimes follows inflammation in the structure of
the brain affecting the connective tissues, which eventually become
hypertrophied and press upon nerve cells and fibers, causing their
ultimate disappearance, leaving the parts hard and indurated. This
condition gives rise to a progressive paralysis and may extend along a
certain bundle of fibers into the spinal cord. Complete paralysis almost
invariably supervenes and causes death.
_Lesions._--On making post-mortem examinations of horses which have died
in the first stages of either of these diseases we find an excessive
engorgement of the capillaries and small blood vessels, with
correspondingly increased redness and changes in both the contents and
the walls of the vessels. If death has occurred at a later period of the
disease, it will be found that, in addition to the redness and
engorgement, an exudation of the contents of the blood vessels into the
tissues and upon the surfaces of the inflamed parts has supervened. If
the case has been one of encephalitis, there will usually be found more
or less watery fluid in the ventricles (natural cavities in the brain),
in the subarachnoid space, and a serous exudation between the
convolutions and interstitial spaces of the gray matter under the
membranes of the brain. The quantity of fluid varies in different cases.
Exudations of a membranous character may be present, and are found
attached to the surfaces of the pia mater.
In meningitis, especially in chronic cases, in addition to the serous
effusion, there are changes which may be regarded as characteristic in
the formation of a delicate and highly vascular layer or layers of
membrane or organized structure on the surface of the dura mater, and
also indications of hemorrhages in connection with the membranous
formations. Hematoma, or blood tumors, may be found embedded in this
membrane. In some cases the hemorrhages are copious, causing paralysis
or apoplexy, followed by speedy death. The meningitis may be
suppurative. In this case a puslike exudate is found between the
membranes covering the brain.
In cerebritis, or inflammation of the interior of the brain, there is a
tendency to softening and suppuration and the formation of abscesses. In
some cases the abscesses are small and numerous, surrounded with a
softened condition of the brain matter, and sometimes we may find one
large abscess. In cases of recent development the walls of the
abscesses are fringed and ragged and have no lining membrane. In older
or chronic cases the walls of the abscesses are generally lined with a
strong membrane, often having the appearance of a sac or cyst, and the
contents have a very offensive odor.