Spasm is a marked symptom in many diseases of the brain and of the spinal cord. Spasms may result from irritation of the motor nerves as conductors, or may result from irritation of any part of the sympathetic nervous system, and they usually indicate an excessive action of the reflex motor centers. Spasms may be induced by various medicinal agents given in poisonous doses, or by effete materials in the circulation, such as nux vomica or its alkaloid strychnia, lead preparations, or an excess of the urea products in the circulation, etc. Spasms may be divided into two cla.s.ses: Tonic spasm, when the cramp is continuous or results in persistent rigidity, as in teta.n.u.s; clonic spasm, when the cramping is of short duration, or is alternated with relaxations. Spasms may affect involuntary as well as the voluntary muscles, the muscles of the glottis, intestines, and even the heart. They are always sudden in their development.

_Spasm of the glottis._--This is manifested by a strangling respiration; a wheezing noise is produced in the act of inspiration; extreme anxiety and suffering for want of air. The head is extended, the body profusely perspiring; pulse very rapid; soon great exhaustion becomes manifest; the mucous membranes become turgid and very dark colored, and the animal thus may suffocate in a short time.

_Spasm of the intestines._--(See "Cramp colic," p. 74.)

_Spasm of the neck of the bladder._--This may be due to spinal irritation or a reflex from intestinal irritation, and is manifested by frequent but ineffectual attempts to urinate.

_Spasm of the diaphragm, or thumps._--Spasmodic contraction of the diaphragm, the princ.i.p.al muscle used in respiration, is generally occasioned by extreme and prolonged speeding on the race track or road.

The severe strain thus put upon this muscle finally induces irritation of the nerves controlling it, and the contractions become very forcible and violent, giving the jerking character known among hors.e.m.e.n as "thumps." This condition may be distinguished from violent beating of the heart by feeling the pulse beat at the angle of the jaw, and at the same time watching the jerking movement of the body, when it will be discovered that the two bear no relation to each other. (See "Palpitation of the heart," p. 259.)

_Spasm of the thigh, or cramp of a hind limb._--This is frequently witnessed in horses that stand on sloping plank floors--generally in cold weather--or it may come on soon after severe exercise. It is probably due to an irritation of the nerves of the thigh. In cramps of the hind leg the limb becomes perfectly rigid, and attempts to flex are unsuccessful; the animal stands on the affected limb, but is unable to move it; it is unnaturally cold; it does not, however, appear to cause much suffering unless attempts are made to change position. This cramp may be of short duration--a few minutes--or it may persist for several days. This condition is often taken for a dislocation of the stifle joint. In the latter the foot is extended backward, and the horse is unable to advance it, but drags the limb. An examination of the joint also reveals a change in form. Spasms may affect the eyelids, by closure or by retraction. Spasm of the sterno-maxillaris muscle has been witnessed, and the animal was unable to close the jaws until the muscle became relaxed.

_Treatment of spasms._--An anodyne liniment, composed of chloroform 1 part and soap liniment 4 parts, applied to cramped muscles will usually cause relaxation. This may be used when single external muscles are affected. In spasms of the glottis, inhalation of sulphuric ether will give quick relief. In spasm of the diaphragm, rest and the administration of half an ounce of chloroform in 3 ounces of whisky, with a pint of water added, will generally suffice to bring relief, or if this fails give 5 grains of sulphate of morphia by hypodermic injection. If spasms result from organic disease of the nervous system, the latter should receive such treatment as its character demands. In cramp of the leg, compulsory movement usually causes relaxation very quickly; therefore the animal should be led out of the stable and be forced to run or trot. Sudden, nervous excitement caused by a crack of the whip or smart blow will often bring about immediate relief. Should this fail, the anodyne liniment may be used along the inside of the thigh, and chloroform, ether, or laudanum given internally. An ounce of the chloral hydrate will certainly relieve the spasm when given internally, but the cramp may return soon after the effect has pa.s.sed off, which in many cases it does very quickly.

_Convulsions._--Although there is no disease of the nervous system which can be properly termed convulsive, or justify the use of the word convulsion to indicate any particular disease, yet it is often such a prominent symptom that a few words may not be out of place. General, irregular muscular contractions of various parts of the body, with unconsciousness, characterize what we regard as convulsions, and like ordinary spasms are dependent upon some disease or irritation of the nervous structures, chiefly of the brain. No treatment is required; in fact, a general convulsion must necessarily be self-limited in its duration. Suspending, as it does, respiratory movements, checking the oxygenation and decarbonization of the blood, the rapid acc.u.mulation of carbonic-acid gas in the blood and the exclusion of oxygen quickly puts the blood in a condition to produce the most reliable and speedy sedative effect upon the nerve excitability that could be found, and consequently furnishes its own remedy so far as the continuance of the convulsive paroxysm is concerned. Whatever treatment is inst.i.tuted must be directed toward a removal of the cause of the convulsive paroxysm.

Ch.o.r.eA, OR ST. VITUS'S DANCE.

Ch.o.r.ea is characterized by involuntary contractions of voluntary muscles. This disease is an obscure disorder, which may be from pressure upon a nerve, cerebral or spinal sclerosis, small aneurisms in the brain, etc. Ch.o.r.eic symptoms have been produced by injecting granules of starch into the arteries entering the brain. Epilepsy and other forms of convulsions simulate ch.o.r.ea in appearance.

Stringhalt is by some termed "ch.o.r.ea." This is manifested by a sudden jerking up of one or both hind legs when the animal is walking. This symptom may be very slight in some horses, but has a tendency to increase with age. In some the catching up of the affected leg is very violent, and when it is lowered to the ground the motion is equally sudden and forcible, striking the foot to the ground like a pile driver.

Very rarely ch.o.r.ea may be found to affect one of the fore legs, or the muscles of one side of the neck or the upper part of the neck.

Involuntary jerking of the muscles of the hip or thigh is seen occasionally, and is termed "shivering" by hors.e.m.e.n.

Ch.o.r.ea is often a.s.sociated with a nervous disposition, and is not so frequent in animals with a sluggish temperament. The involuntary muscular contractions cause no pain, and do not appear to produce much exhaustion of the affected muscles, although the jerking may be regular and persistent whenever the animal is in motion.

_Treatment._--In a few cases, early in the appearance of this affection, general nerve tonics may be of benefit, viz, iodid of iron, 1 dram; pulverized nux vomica, 1 dram; pulverized scutellaria (skull-cap), 1 ounce. Mix and give in the feed once a day for two weeks. a.r.s.enic in the form of Fowler's solution is often beneficial. If the cause is connected with organic brain lesions, treatment is usually unsuccessful.

EPILEPSY, OR FALLING FITS.

The cause of epilepsy is seldom traceable to any special brain lesions.

In a few cases it accompanies disease of the pituitary body, which is located in the under surface of the brain. Softening of the brain may give rise to this affection. Attacks may occur only once or twice a year or they may be of frequent recurrence.

_Symptoms._--No premonitory symptoms precede an epileptic fit. The animal suddenly staggers; the muscles become cramped; the jaws may be spasmodically opened and closed, and the tongue become lacerated between the teeth; the animal foams at the mouth and falls in a spasm. The urine flows involuntarily, and the breathing may be temporarily arrested. The paroxysm soon pa.s.ses off, and the animal gets on its feet in a few minutes after the return of consciousness.

_Treatment._--Dashing cold water on the head during the paroxysm. After the recovery 1 dram of oxid of zinc may be given in the feed twice a day for several weeks, or benefit may be derived from the tonic prescribed for ch.o.r.ea.

PARALYSIS, OR PALSY.

Paralysis is a weakness or cessation of the muscular contraction by diminution of loss of the conducting power or stimulation of the motor nerves. Paralytic affections are of two kinds, the complete and the incomplete. The former includes those in which both motion and sensibility are affected; the latter those in which only one or the other is lost or diminished. Paralysis may be general or partial. The latter is divided into hemiplegia and paraplegia. When only a small portion of the body is affected, as the face, a limb, the tail, it is designated by the term local paralysis. When the irritation extends from the periphery of the center it is termed reflex paralysis.

Causes are much varied. Most of the acute affections of the brain and spinal cord may lead to paralysis. Injuries, tumors, disease of the blood vessels of the brain, etc., all have a tendency to produce suspension of the conducting motive power to the muscular structures.

Pressure upon, or the severing of, a nerve causes a paralysis of the parts to which such a nerve is distributed. Apoplexy may be termed a general paralysis, and in nonfatal attacks is a frequent cause of the various forms of palsy.

GENERAL PARALYSIS.--This can not take place without producing immediate death. The term is, however, usually applied to paralysis of the four extremities, whether any other portions of the body are involved or not.

This form of palsy is due to compression of the brain by congestion of its vessels, large clot formation in apoplexy, concussion, or shock, or any disease in which the whole brain structure is involved in functional disturbance.

HEMIPLEGIA (PARALYSIS OF ONE SIDE OR HALF OF THE BODY).--Hemiplegia is frequently the result of a tumor in the lateral ventricles of the brain, softening of one hemisphere of the cerebrum, pressure from extravasated blood, fracture of the cranium, or it may be due to poisons in the blood or to reflex origin. When hemiplegia is due to or the result of a prior disease of the brain, especially of an inflammatory character, it is seldom complete; it may affect only one limb and one side of the head, neck, or muscles along the back, and may pa.s.s off in a few days after the disappearance of all the other evidences of the primary affection.

In most cases, however, hemiplegia arises from emboli obstructing one or more blood vessels of the brain, or the rupture of some vessel the wall of which had become weakened by degeneration and the extravasation of blood. Sensibility in most cases is not impaired, but in some there is a loss of sensibility as well as of motion. In some cases the bladder and r.e.c.t.u.m are involved in the paralysis.

_Symptoms._--In hemiplegia the attack may be very sudden, and the animal fall, powerless to move one side of the body; one side of the lips will be relaxed; the tongue may hang out on one side of the mouth; the tail curved around sideways; an inability to swallow feed or water may be present, and often the urine dribbles away as fast as it collects in the bladder. Sensibility of the affected side may be entirely lost or only partial; the limbs may be cold and sometimes unnaturally warm. In cases wherein the attack is not so severe the animal may be able to maintain the standing position, but will have great difficulty in moving the affected side. In such cases the animal may recover from the disability.

In the more severe, in which there is complete loss of power of movement, recoveries are rare.

PARAPLEGIA (TRANSVERSE PARALYSIS OF THE HIND EXTREMITIES).--Paralysis of the hind extremities is usually due to some injury or inflammation affecting the spinal cord. (See "Spinal meningitis," p. 232, and "Myelitis," p. 233.) It may also be due to a reflex irritation from disease of peripheral nerves, to spinal irritation or congestion caused by blood poisons, etc.

_Symptoms._--When due to mechanical injury of the spinal cord, from a broken back or spinal hemorrhage, it is generally progressive in its character, although it may be sudden. When it is caused by agents in the blood, it may be intermittent or recurrent.

Paraplegia is not difficult to recognize, for it is characterized by a weakness and imperfect control of the hind legs and powerless tail. The urine usually dribbles away as it is formed and the manure is pushed out, ball by ball, without any voluntary effort, or the pa.s.sages may cease entirety. When paraplegia is complete, large and ill-conditioned sores soon form on the hips and thighs from chafing and bruising, which have a tendency quickly to weaken the animal and necessitate his destruction.

LOCOMOTOR ATAXIA, OR INCOORDINATION OF MOVEMENT.--This is characterized by an inability to control properly the movement of the limbs. The animal appears usually perfectly healthy, but when he is led out of his stall his legs have a wobbly movement and he will stumble or stagger, especially in turning. When this is confined to the hind parts it may be termed a modified form of paraplegia, but often it may be seen to affect nearly all the voluntary muscles when they are called into play, and must be attributed to some pressure exerted on the base of the brain.

LOCAL PARALYSIS.--This is frequently met with in horses. It may affect many parts of the body, even vital organs, and it is very frequently overlooked in diagnosis.

FACIAL PARALYSIS.--This is a frequent type of local paralysis, and is due to impairment of function of the motor nerve of the facial muscles, the portio dura. The cause may exist at the base of the brain, compression along its course after it leaves the medulla oblongata, or to a bruise after it spreads out on the great ma.s.seter muscle.

_Symptoms._--A flaccid condition of the cheek muscles, pendulous lips, inability to grasp the feed, often a slow and weak movement in chewing, and difficulty and slowness in drinking.

LARYNGISMUS PARALYTICUS, OR ROARING.--This condition is characterized by roaring, and is usually caused by an inflamed or hypertrophied bronchial gland pressing against the left recurrent laryngeal nerve, which interferes with its conducting power. A similar condition is occasionally induced in acute pleurisy, when the recurrent nerve becomes involved in the diseased process or compressed by plastic exudation.

PARALYSIS OF THE r.e.c.t.u.m AND TAIL.--This is generally the result of a blow or fall on the rump, which causes a fracture of the sacrum bone and injury to the nerves supplying the tail and part of the r.e.c.t.u.m and muscles belonging thereto. This fracture would not be suspected were it not for the loss of motion of the tail.

INTESTINAL PARALYSIS.--Characterized by persistent constipation; frequently the strongest purgatives have no effect whatever on the movement of the bowels. In the absence of symptoms of indigestion, or special diseases implicating the intestinal ca.n.a.l, torpor of the bowels must be attributed to deficient innervation. This condition may depend upon brain affections or be due to reflex paralysis. Sudden checks of perspiration may induce excessive action of the bowels or paralysis.

PARALYSIS OF THE BLADDER.--This usually affects the neck of the bladder, and is characterized by incontinence of urine; the urine dribbles away as fast as it is secreted. The cause may be of reflex origin, disease of the r.e.c.t.u.m, tumors growing within the pelvic cavity, injury to the spinal cord, etc.

PARALYSIS OF THE OPTIC NERVE (AMAUROSIS).--A paralysis of eyesight may occur very suddenly from rupture of a blood vessel in the brain, acute local congestion of the brain, the administration of excessive doses of belladonna or its alkaloid atropia, etc. In amaurosis the pupil is dilated to its full extent; the eye looks clear, but does not respond to light.

Paralysis of hearing, of the external ear, of the eyelid, partial paralysis of the heart and organs of respiration, of the blood vessels from injury to the vasomotor nerves of the esophagus, or loss of deglut.i.tion, palsy of the stomach, all may be manifested when the supply of nervous influence is impaired or suspended.

TREATMENT FOR PARALYSIS.--In all paralytic affections there may be anesthesia, or impairment of sensibility, in addition to the loss of motion, or there may be hyperesthesia, or increased sensibility, in connection with the loss of motion. These conditions may call for special treatment in addition to that for loss of motion. If hyperesthesia is well marked local anodynes may be needed to relieve suffering. Chloroform liniment or hypodermic injections of from 3 to 5 grains of sulphate of morphia will allay local pain. If there is marked anesthesia, or loss of sensibility, it may become necessary to secure the animal in such way that he can not suffer serious injury from accidents which he can not avoid or feel. In the treatment of any form of paralysis we must always refer to the cause, and attempt its removal if it can be discovered. In cases in which the cause can not be determined we have to rely solely upon a general external and internal treatment. Externally, fly blisters or strong, irritant liniments may be applied to the paralyzed parts. In hemiplegia they should be applied along the bony part of the side of the neck; in paraplegia, across the loins. In, some cases hot-water cloths will be beneficial. Internally, it is well to administer 1 dram of powdered nux vomica or 2 grains of sulphate of strychnia twice a day until twitching of some of the voluntary muscles occurs; then discontinue it for several days, and then commence again with a smaller dose, gradually increasing it until twitching recurs. Iodid of pota.s.sium in 1 to 2 dram doses two or three times daily may be used with the hope that it will favor the absorption of the clot or obstruction to the nervous current. In some cases Fowler's solution of a.r.s.enic in teaspoonful doses twice a day in the drinking water proves beneficial. Occasionally benefit may be derived from the application of the electric current, especially in cases of roaring, facial paralysis, paralysis of the eyelid, etc. Nutritious but not too bulky feed, good ventilation, clean stabling, moderate exercise if the animal is capable of taking it, good grooming, etc., should be observed in all cases.

SPINAL MENINGITIS, OR INFLAMMATION OF THE MEMBRANES ENVELOPING THE SPINAL CORD.

This may be induced by the irritant properties of blood poisons, exhaustion and exposure, spinal concussion, all forms of injury to the spine, tumors, caries of the vertebrae, rheumatism, etc.

_Symptoms._--A chill may be the precursor, a rise in temperature, or a general weakness and shifting of the legs. Soon a painful, convulsive twitching of the muscles sets in, followed by muscular rigidity along the spine, in which condition the animal will move very stiffly and evince great pain in turning. Evidences of paralysis or paraplegia develop, retention or incontinence of urine, and oftentimes s.e.xual excitement is present. The presence of marked fever at the beginning of the attack, a.s.sociated with spinal symptoms, should lead us to suspect spinal meningitis or myelitis. These two conditions usually appear together, or myelitis follows inflammation of the meninges so closely that it is almost impossible to separate the two; practically it does not matter much, for the treatment will be about the same in both cases.

Spinal meningitis generally becomes chronic, and is then marked princ.i.p.ally by paralysis of that portion, or parts of it, posterior to the seat of the disease.

_Pathology._--In spinal meningitis we find essentially the same condition as in cerebral meningitis; there is an effusion of serum between the membranes, and often a plastic exudation firmly adherent to the pia mater serves to maintain a state of paralysis for a long time after the acute symptoms have disappeared by compressing the cord.

Finally, atrophy, softening, and even abscess may develop within the cord. Unlike in man, it is usually found localized in horses.

_Treatment._--Bags filled with ice should be applied along the spine, to be followed later by strong blisters. The fever should be controlled as early as possible by giving 20 drops of Norwood's tincture of veratrum viride every hour until the desired result is obtained. One dram of the fluid extract of belladonna, to control pain and vascular excitement of the spinal cord, may be given every five or six hours until the pupils of the eyes become pretty well dilated. If the pain is very intense 5 grains of sulphate of morphia should be injected hypodermically. The animal must be kept as free from excitement as possible. If the urine is retained in the bladder it must be drawn off every four or six hours. In very acute attacks the disease generally proves fatal in a few days. If, however, the animal grows better, some form of paralysis is liable to remain for a long time, and the treatment will have to be directed then toward a removal of the exudative products and a strengthening of the system and stimulation of the nervous functions. To induce absorption, iodid of pota.s.sium in 2-dram doses, dissolved in the drinking water, may be given twice a day. To strengthen the system, iodid of iron 1 dram twice a day and 1 dram of nux vomica once a day may be given in the feed. Electricity to the paralyzed and weakened muscles is advisable; the current should be weak, but be continued for half an hour two or three times daily. If the disease is due to a broken back, caries of the vertebrae, or some other irremediable cause, the animal should be destroyed at once.

MYELITIS, OR INFLAMMATION OF THE SUBSTANCE OF THE SPINAL CORD.