Chapter VI: Part 6

Sore throat is fortunately even more rare than in the larger ruminants. It occurs chiefly where this animal, constituted to feed on the dainty grasses of the dry mountain side, is kept on cold, marshy ground and exposed to frequent cold, wet blasts. Sheep suffer also from hot, close, filthy buildings in winter, and from unseasonable clipping.

The _symptoms_ are frequent coughing and sneezing, running from the nose, working of the jaws, and breathing through the open mouth as being easier than through the plugged nostrils. The larynx is tender and may be swollen.

_Treatment_ is usually confined to ventilation and cleansing of the fold, frequent fumigations with water vapor from the spout of a boiling kettle, and with sulphur fumes, and giving tepid farinaceous gruels or mashes containing sulphate of soda in the daily proportion of two pounds to each hundred head of sheep. Sal ammoniac may be given in food or drinking water.

LARYNGITIS IN PIG.

Frequency. Causes, wet, cold pens, exposure, withholding liquids.
Symptoms, prostration, dullness, cough, fever, swollen throat and
neck, dyspnœa, dark mucosa, sloughing of epithelium and epidermis,
general petechiæ, fœtid breath, great prostration. Lesions, gangrenous
patches on pharynx and fauces, ulcers, infiltrations. Treatment,
hygienic, dietetic, emetic, laxative, poultice, bandages, locally,
astringent, antiseptic, caustic, tonic.

Sore throat is common in some localities when pigs live in herds.

_Causes._ Chiefly faulty hygiene. Exposed, cold and wet piggeries, cold blasts for which the pig has an extraordinary aversion, and the deprivation of liquids in warm, dry seasons are frequent causes.

_Symptoms._ These have been described by M. Pradal, who divides the disease into three stages, evidently dealing with an infectious malady. The _first stage_ is marked by loss of appetite, dullness, slow, listless movements, a tendency to hide under the litter; low, hoarse grunt and cough, the last aggravated by moving the animal; pain in swallowing; red, sunken eye, and constipation. If there is no improvement on the second or third day it merges into the _second stage_. This is characterized by a still hoarser grunt, painful, hard hacking cough, difficult breathing, especially in the sunshine, and a rapidly increasing swelling of the throat, soon extending to both ears and as far down as the breast bone. This engorgement feels soft and pasty though firm, tender lumps may be felt, indicating the approaching formation of abscess. It is so abundant that suffocation may ensue in the course of forty-eight hours. If the progress of the swelling is not arrested it soon passes into the _third_ or _gangrenous stage_. The breathing is more hurried; the mouth open, the protruded tongue of a bluish black color, the cough followed by a continuous rattle, the head unsteady, swallowing impossible, and the swelling extends to the side of the face and beneath the chest. The swollen surface is cold and livid; the bristles easily detached; it is bedewed by a serosity which exudes from it, and portions of the dead skin tend to detach themselves. The mouth and throat participate in the gangrene, the breath, saliva and nasal discharge is fetid, and the epidermis peels off. The snout, ears and skin generally assume a bluish black hue, the prostration is extreme, the creature lying constantly on its side; the pain ceases and in one or two days death ensues, preceded by a state of comparative calmness.

On opening the throat after death the mucous membrane is engorged and thickened, bears various hues of black, blue, livid and green, and breaks down into a pulpy mass under slight pressure. The surrounding (pharyngeal) muscles even are implicated in this change. In the earlier stages there is only engorgement with blood of the tonsils and the mucous membrane of the pharynx and larynx; serous infiltration of the surrounding parts, and often the presence of inspissated mucus resembling false membranes or of ulcers on the surface.

_Treatment._ In the earlier stages, hygienic measures alone may suffice to check. A warm, dry, comfortable piggery, emollient and astringent drinks, such as sheep’s head broth, oatmeal and other gruels acidulated with vinegar or buttermilk, an emetic (six grains of tartar emetic); a dose of physic (four croton beans powdered and given in the food, or from two to three ounces of castor oil), and if the patient will permit it a flannel bandage or piece of sheepskin round the throat. If the symptoms are more threatening it is recommended to bleed from the ears and tail; to apply a linseed meal poultice round the throat to hasten the formation of abscess, or in the absence of such indications to employ a mustard poultice made with spirits of turpentine, or rugs wrung out of boiling water, to the same part. Local astringent and caustic applications to the throat are the most promising, applied by means of a whalebone prob as recommended for other animals, the mouth being held open by a noose round the upper jaw. Sodium sulphite, silver nitrate, potassium permanganate, hydrochloric acid diluted, and tincture of iodine, may be employed.

When the gangrenous stage has been reached all treatment is useless.

LARYNGITIS IN THE DOG.

Sore throat is chiefly seen in pampered pets and in hunting dogs, as
the greyhound. In the latter class it is the result of chills, a cold
ducking when heated, cold damp kennels, etc. It is sometimes almost
the only manifestation of distemper.

_Symptoms._ Dullness, impaired appetite, a slight cough becoming more frequent and paroxysmal. These paroxysms give rise to accelerated and panting breathing, and if severe, to the ejection of a glairy yellow (bilious) material from the stomach. There is also running from the nose and frequent sneezing. The dull muffled bark has led to the supposition of _rabies_ but it has no resemblance whatever to the characteristic cry of _rabies_ while beginning like an impulsive bark merges into an agonized and baffled howl. Accelerated pulse, elevated temperature, reddened fauces and swollen tonsils are marked symptoms.

Sometimes a short, dry cough obstinately remains after the disease has apparently subsided.

_Treatment._ Attend to general comfort, steam the nostrils, give a laxative if costive, and follow with iodide of potassium or salammoniac (5 grains) repeated thrice daily. Apply a mustard poultice to the throat.

PHARYNGITIS. SORE THROAT.

Causes. Symptoms, larynx insensible, tender parotid and submaxillary
swelling, cough mucous, difficult swallowing with gurgling, liquids
returned by nose, buccal mucosa hot and red, salivation, chronic
cases. Treatment, medicated drinks and electuaries.

ANGINA PHARYNGEA. CYNANCHE PHARYNGEA.

Inflammation of the pharynx owes its existence to the same _causes_ as _Laryngitis_.

_Symptoms._ The general symptoms being like those of _Laryngitis_, the specific and distinguishing ones only will be here noticed. The larynx is not tender to the touch nor is cough thereby excited. The glands beneath the root of the ears (parotids) are swollen and tender and cough is induced by handling them. The intermaxillary glands are enlarged. The cough is loose and followed by the ejection of glairy materials by the mouth and nose. Food and drink are swallowed with difficulty and effort, dry grain or hay is often refused, or dropped from the mouth, after it has been chewed, to avoid the pain of swallowing. Deglutition is accompanied by a gurgling sound caused by the abundant secretion in the pharynx. In swallowing liquids a portion is often rejected by the nose. The mouth is hot, red at its back part, and filled with fetid saliva which often drivels from between the lips in the coarser breeds of horses. The fever varies according to the intensity of the inflammation. This disease is rarely serious, and improvement is manifested, by a free discharge from the nose of a white opaque color, by the ability to swallow without pain, and the better appetite and general appearance. Collections of pus in the _Guttural pouches_ may result from pharyngitis. See _Chronic Nasal Catarrh_.

Reynal has seen chronic cases of this disease due to: 1st, fracture of the large branch of the hyoid bone; 2nd, Laceration or ulceration of the soft palate; and 3rd, an abscess of the pharyngeal mucous membrane.

The _treatment_ does not differ materially from that of laryngitis except in the greater value of soft food, mucilaginous and acidulated drink and of electuaries which act on the throat as they dissolve. Subjoined is a formula:

Recipe: Extract Belladonna, four drams; potassium iodide, one ounce; sodium hyposulphitis, three ounces; mellis, five ounces. Mix. A desert spoonful to be smeared on the inside of the cheek thrice daily.

CROUP.

Croup: croak. Acute laryngitis, with spasms and perhaps
pseudo-membranes. Relation to diphtheria. Causes, low, damp
localities, exposure, youth, form of inflammation. Symptoms, onset
sudden, crowing inspiration, hard cough paroxysmal, fever, larynx
sensitive, dyspnœa in paroxysms or intermittent. Complications.
Duration. Lesions, intense congestion, false membranes on larynx,
fibrinous. Treatment, fomentations, ether, chloroform, chloral
hydrate, laxative saline, sedative, derivative, surgical, water vapor,
calomel, caustic, stimulants, tonics. Croup in sheep and horse.

CROUPOUS LARYNGITIS. PSEUDO-MEMBRANOUS LARYNGITIS.

_Name and Definition._ The word _croup_ by which this disease is known over the whole of Europe and a great part of America is, essentially _Scotch_, and is familiarly used in the Lowlands of Scotland to signify—_to croak_. The disease consists in an acute inflammation or high vascular irritation of the larynx, associated with spasms of its muscles and commonly though not invariably with a firm layer of exudation on the surface of the mucous membrane. In some cases undoubtedly croup is but a form of the contagious pseudo-membranous affection diphtheria, the germs of which grown on a surface freely swept by continuous currents of pure air, retain too much of an ærobic habit to penetrate deeply into the tissues. (See Authors, “Malignancy mitigated by Oxygen,” Medical Record, 1881, p. 673). It does not follow, however, that croup is always due to even a weakened germ. So far as yet appears it may develop independently of any particular pathogenic germ, from some violent local irritant in a predisposed subject. Croup therefore may be treated here as a presumably noninfectious disease. Being a very rare disease in horses its manifestation in ruminants will first be noticed.

CROUP IN THE OX.

_Causes._ These are not well understood. Low, damp situations would seem most liable, especially if the animals are much exposed at night. So far indeed as can be observed it arises from the same causes as _laryngitis_. Age affects its development. Croup is mostly seen in animals between six months and a year old, and rarely in those over five or six years of age. The specific cause of the formation of false membranes and of spasms of the laryngeal muscles is a mystery, but to these the susceptible constitution and tissues of young animals appear to predispose. No mere grade of inflammation from the slightest hyperæmia to the highest type of inflammatory action is of itself sufficient to arouse the special phenomena. All of these are seen everywhere but _croup_ may be said to be confined to certain localities and ages.

_Symptoms._ Unless it supervenes on a pre-existant attack of catarrh, croup is usually as sudden in its outset in the lower animals as in man. An extremely hard _croupy_ cough, or loud, crowing, difficult breathing, loudest in inspiration, is usually the first symptom and appears to seize the animal in an instant and without the slightest premonition. This is closely followed by intense fever, full, hard pulse, 80 to 100 and upward per minute, increase of bodily temperature sometimes to 107.5° F., costiveness and high colored scanty urine. The throat is excessively tender, the slightest touch giving rise to violent paroxysms of coughing, during which the eyes redden and protrude from their sockets, the veins of the skin are gorged, the tongue, dry and livid, is protruded and small portions of the contents of the stomach and white shreds of false membrane are occasionally brought up. Sometimes in the intervals of coughing as well the mouth is constantly open and the tongue protruded and partly covered by a frothy but tenacious mucus. Suffocation appears imminent in many cases and the beast may perish suddenly in this way. On the other hand the threatening symptoms may be present only at certain periods of the day and may be moderated remarkably at others, especially at early morning. If complicated by any chest affection the symptoms are more urgent and the issue more commonly fatal. If associated with a low type of fever, a small, weak pulse, and much prostration, as it tends to be if it continues several days without relief, it has a more fatal tendency. The same may be said of its occurrence epizootically.

_Duration._ Croup will often run its course and prove fatal in twenty-four to forty-eight hours. Improvement is manifested by the cough becoming less convulsive and painful, by the expulsion through the mouth of shreds of false membrane, and by return of spirits and appetite.

_Postmortem Appearances._ If the animal has died suffocated, the lungs and right side of the heart will be gorged with blood; if in a stupor (coma), attendant on brain poisoning with venous blood, the veins will be specially engorged. The mucous membrane of the larynx has a more vivid arborescent redness than in ordinary laryngitis but the special feature is the presence of false membranes. These layers of exuded material are almost confined to the air passages. They may extend to the soft palate and nose in an upward direction and to the trachea and bronchial tubes in a downward, but they rarely exist in the mouth, pharnyx, or gullet like the false membranes of diphtheria.

_Characters of the false membranes._ These are gray or yellowish white, though they may be reddened in patches or streaks. They vary in consistency from that of glairy mucus to a firm layer as of dense fibrine, and become more adherent as they are of older standing. Sometimes they are partially detached, the free end of the shreds floating in the larynx. The deep or attached surface presents redness in points, in streaks, or as ramifications very visible if the membrane is held up between the eye and the light. They vary in thickness from half to a line. Delafond has found these membranes in the lower animals to be mostly formed of fibrine, with a little albumen, and traces of alkaline and earthy salts.

_Treatment._ This must be prompt and energetic. Wet cloths as hot as the hands can bear, wrapped around the throat and neck, and replaced as they cool, will usually arrest the spasm. If this fails ether or chloroform by inhalation or chloral hydrate by injection may be employed with caution. The action of the bowels must be secured by salines (sulphate of soda ½ to 1 ℔) or oil (linseed oil ½ to 1 pint) and injections of warm water. Sulphate of soda should be thereafter given in half ounce doses twice daily, or nitrate or acetate of potass may be substituted. They are advantageously given in linseed decoction and may be combined with laudanum, (½ ounce), belladonna, or other agent to check the spasms.

A blister (mustard poultice) should be applied at first either to the throat or breast, the windpipe being left untouched lest tracheotomy should be required. Similar applications to the legs are useful.

If suffocation appears imminent _tracheotomy_ should be at once performed (see under Laryngitis). This operation has been depreciated because of the late period at which it has been employed, when the patient was already past all hope, but the resulting wound in the neck is more than counterbalanced by the greater freedom of breathing and the better æration of the blood which tends to obviate the justly dreaded low fever. It often leads to a rapid diminution of the spasms and laryngeal irritation.

Agents applied directly to the inflamed mucous membrane are often requisite. The air of the building should be rather warm, equable and moistened by water vapor, if that can be conveniently done. Calomel or alum powder may be frequently introduced into the larynx by means of a whalebone prob and sponge as spoken of under laryngitis, or a solution of nitrate of silver (10 grains to the ounce of water) may be applied several times a day. These not only hasten the removal of false membranes but counteract their production. They produce violent and convulsive coughing at first and have to be used carefully. Delafond blew in such agents through an opening made in the windpipe. They may be injected with a hypodermic syringe. In prostrate conditions it may be necessary to resort to stimulants (wine whey, carbonate of ammonia) and tonics (gentian, Peruvian bark).

CROUP IN SHEEP.

According to Roche Lubin croup is sometimes observed in spring in lambs and hogs. The common cause is “the shutting up of the animals for the whole twenty-four hours in a hot confined place, the floor of which is covered by a fine dust, and the air loaded with the same, owing to the jostling of the sheep together, the effects being intensified by the weight of the fleeces.”

The disease is manifested by constant working of the jaws, extreme tension of the neck, abundant salivation, respiration hurried and whistling, extreme pain and threatened suffocation when the slightest pressure is made on the throat, and refusal of all food liquid or solid. The weak, hacking, convulsive cough is associated with the discharge of a whitish glairy mucus by the nose until the third or fourth day when false membranes may be expected.

_Treatment_ is like that for the ox, medicine being given in about one-fifth of the doses.

CROUP IN THE HORSE.

The rare cases of _croup_ in foals and young horses appear due to the same general causes as in ruminants. M. Riss records two cases, and Bouley one from breathing smoke when the straw of the stable had taken fire. The suddenness of the attack, the spasmodic symptoms and the duration of the disease and the treatment do not differ materially from those given for the ox.

PHARYNGEAL AND LARYNGEAL POLYPI.

Pediculated tumors. Dyspnœa through change of position, operation by
ecraseur, snare, or cricoid incision.

Tumors of varied structure developing in or beneath the mucosa of pharynx or larynx often become slowly detached until they hang by a loose pedicle, and having much latitude of movement they may at times slip between the arytenoid cartilages or even into the glottis producing the most urgent or even fatal dyspnœa. Pediculated tumors in the posterior nares lead to the same accident. In one case of multiple small tumors on the pharyngeal mucosa of the horse, the largest and loosest, attached to the front of the epiglottis, was occasionally displaced into the larynx threatening instant asphyxia. One such attack supervened on the opening of a suppurating guttural pouch by the writer, necessitating prompt tracheotomy. A time was set for the removal of the polypus, but the tracheotomy tube having been accidentally displaced during the preceding night the patient died of suffocation. Dick mentions a polypus growing from the interior of the larynx and causing loud _roaring_. Such tumors may be removed by operating with the _ecraseur_ through the mouth, or by a snare passed through a long narrow tube and used to seize and twist through the pedicle. If the polypus grows from the laryngeal walls, it may be best reached by incision through the cricoid cartilage and crico-thyroid membrane as in the operation for _roaring_.

DYSPNŒA LARYNGEA. ROARING. HEMIPLEGIA LARYNGEA.

Generic name for common symptom. Low and high notes. Grunter, roarer,
whistler, piper, highblower. Pace or effort develops. Causes: of
temporary roaring, inflammations, abscess, phlebitis, choking, dropsy,
petechial fever, phlegmons along vagus. Causes of inveterate roaring,
paresis of left recurrent laryngeal nerve, fatty degeneration of left
arytenoid muscles, fracture of facial bones, polypi in air passages,
chronic thickening of mucosa, foreign bodies in passages, tumors of
lymph glands, abscess of guttural pouches, pseudo membrane, laryngeal
ulceration, ossification, distortion, fracture of cartilages, action
of forcible inspiration, leading on left side, deep origin of
recurrent nerve, effect of chest diseases and violent heart action,
examples of morbid conditions impairing innervation. Lesions in
muscles, and nerves. Facial palsy, poison (chick vetch, winter vetch,
lead, fungi, moulds). Intermittent roaring. Hereditary roaring.
Symptoms, grunting when coughed or threatened, heavy draft, gallop,
noise, laryngeal tremor, cold as a complication, roaring with
expiration, lesions. Treatment, its use. Prevention, avoid breeding
roarers, bearing reins, chick vetch, lead. Tonic medication, caustic
to mucosa, firing, setons, iodine, pad nostrils, tracheotomy,
arytenectomy, electricity.

This is the name of a symptom rather than a disease. It implies a sound made in breathing in connection with some contraction of the air passages. The term is however usually reserved for those conditions in which the sound results, from chronic disease or malformation, the noise attendant on laryngitis and other acute diseases being rarely spoken of as _roaring_. In neither case does the noise indicate more than that there is some impediment to the ingress and egress of air through larynx or trachea.

The pitch of the note varies exceedingly with the causes that produce it and with the hurried nature of the breathing. There have thus arisen the epithets of _grunter_, _roarer_, _whistler_, _highblower_, _piper_, _trumpeter_, _wheezer_, _etc_. The most common distinctions are those of _roaring_ and _whistling_. The _roarer_ produces a loud deep basso sound in inspiration, the larynx or windpipe being only slightly narrowed while the _whistler_ or _piper_ produces a shrill blowing or sibilant noise because of the greater constriction of the passage. The term _grunter_ is derived from the facts that a _roarer_ usually makes a grunting noise when struck or threatened with a cane, and that when the upper cartilages of the windpipe are pinched between the finger and the thumb the resulting cough is prolonged and somewhat like a _grunt_. A _wheezer_ is usually suffering from spasmodic contraction of the bronchial tubes, from broken wind or from chronic bronchitis. A _highblower_ should never be spoken of in the same connection, as the noise is made from a playful flapping of the false nostrils or soft palate and disappears when the animal is put to the top of his speed. It is from confounding _high-blowing_ with _roaring_ that _Eclipse_ and other brilliant performers on the English turf have been erroneously pronounced _roarers_.

The noise produced by the _roarer_ is not heard while he stands quiet, nor many cases even during a short trot or gallop. Such horses are in consequence often sold at the hammer and the purchaser is grievously disappointed to find that what he thought a sound horse is absolutely useless for the purpose for which he designed it.

=Causes.= Before noticing the symptoms of roaring a consideration of the causes will be useful to enable the reader the better to understand the signs by which the different forms are manifested.

=Causes of temporary roaring.= Whatever impedes the current of air causes roaring. Hence inflammatory diseases of the nose, throat, windpipe or bronchial tubes; abscess of one or the other of these parts; inflammation of a jugular vein and pressure on the trachea or vagus nerve by the resulting swelling; choking; the swelling in the neck consequent on the cutting open of the gullet for the relief of choking; thickening of the nostrils from dropsy, loss of a jugular vein, purpura hemorrhagica etc.; and swellings pressing on the vagus nerve, and which may be situated at the base of the brain, in the neck or in the anterior part of the chest. Also temporary infiltration of the laryngeal mucosa.

=Causes of inveterate roaring.= The one great cause of roaring and that which sustains the disease in nineteen cases out of every twenty is paralysis of the left _recurrent nerve_ of the larynx and wasting of several of the arytenoid muscles on that side. It may be well, however, first to notice the less frequent causes and wind up with this more common one. 1st, Fracture with distortion of the nasal bones and narrowing of the nasal passages (Gamgee). 2nd, Polypi and other tumors of the nose, pharynx, larynx, windpipe or bronchi. 3rd, Chronic thickening of the nasal mucous membrane, the result of inflammation. 4th, The presence of foreign bodies in the nose, as for example balls coughed up from the pharynx. 5th, Hering records a case resulting from the closure of the posterior opening of one nasal chamber by a membrane. 6th, Cancerous or melanotic deposits in the lymphatic glands above and to each side of the pharynx and larynx. 7th, Distension of the guttural pouches by inspissated pus. 8th, Chronic thickening of the mucous membrane of the larynx consequent on inflammation. 9th, The formation of a projecting fold of the mucous membrane or of a new production (false membrane) in the windpipe as the result of inflammation. Such false membranes have been known to become detached at their median part and remain attached at their two extremities thus constituting a band stretching from one side of the windpipe to the other. 10th, Ulceration of the membrane of the larynx particularly on the projecting folds circumscribing the glottis, 11th, Ossification of the laryngeal cartilages and loss of their elasticity. 12th, Distortion of the cartilages of the larynx, most commonly from unduly tight reining and pulling the nose in toward the chest. In such cases the cartilages of the larynx and those of the windpipe adjoining being compressed slide within each other, and the enclosed edge projecting within the air tube materially diminishes its calibre. 13th, Fracture of one or more rings of the trachea. This usually results from blows, as in running the neck against the back of a cart or wagon. The cartilaginous rings are usually broken at their median part in front and being retained together by the investing elastic tissue which enables the pieces to move on each other as by a hinge, and being approximated by the contraction of the trachealis muscle above, the ring is flattened from side to side and the channel for the passage of air correspondingly decreased. This flattening can be easily felt by the hand in the living horse. 14th, A peculiar congenital distortion of the trachea caused by the curling in of one end of each cartilage of the windpipe and the straightening out of the other. This occasionally proceeds so far that the gullet is lodged in the interspace overlapped and hidden by the free ends of the cartilages, the diameter of the windpipe being proportionately diminished. Distortions and fractures are usually overlooked by veterinarians but from the frequency with which the author has met with them in his dissection he is convinced that they deserve greater attention than has been awarded them. 15th, Percivall records a case of inveterate _roaring_ in which, even tracheotomy having failed to cure, the patient was destroyed and the lungs found to be extensively consolidated, many of the air tubes having been so compressed as to be almost impervious. I have known a case of roaring from the presence of a pedunculated tumor in the lower end of the windpipe where it divides to enter the lungs, and the same result may ensue from the partial obstruction of the bronchial tubes by masses of tenacious mucus in chronic bronchitis.

16th. The immediate cause of _roaring_ in the immense majority of cases is the =paralysis and fatty degeneration of certain muscles on the left side of the larynx=. The muscles supplied with motive power by the =left recurrent laryngeal nerve= (Crico-arytenoideus posticus, Crico-arytenoideus lateralis, thyro-arytenoideus, and the left half of the arytenoideus) are those constantly and exclusively affected, while those supplied by the _superior laryngeal nerve_ (Crico-thyroideus, hyo-thyroideus and hyo-epiglottideus) remain unchanged. The left recurrent nerve is also wasted and considerably attenuated as compared with that on the opposite side. The _modus operandi_ of this paralysis and wasting in the production of _roaring_ is beautifully seen when the upper part of the windpipe is laid open so as to expose the interior of the larynx in laryngectomy. The triangular opening of the glottis is seen fairly dilated while the muscles are relaxed in the act of expiration. As soon, however, as inspiration commences the left arytenoid cartilage slides completely into the passage, its lower border projecting so much to the right that it forms a prominent crest extending beyond the median line and in some cases closely approaching the right wall of the larynx, the superior elastic and free border of the same cartilage meanwhile gets drawn inward by the suction power of the air so as to block up the passage still more. The closure of the glottis being thus seen to be largely controlled by the current of inspired air, it becomes evident that any increase in the force of the current will aggravate it and a decrease will lessen the extent of the closing and alleviate the distress of breathing. This fact furnishes a means of palliating the symptoms. (See treatment.) It explains moreover why roaring should not be heard in quiet breathing and why it should increase in force and in pitch as the respiration becomes more and more hurried. It further accounts for the noise being heard only during the act of inspiration, the outward rush of the air in the expiratory act being of itself sufficient to carry this valvular cartilage out of the passage and secure a free and unimpeded current.

The paralysis and wasting of the left recurrent nerve and muscles are in their turn due to very varied morbid states.

It may commence in the larynx from distortion of its cartilages and inflammation of the mucosa, in which case the wasting of the nerve is probably a result of its prolonged inactivity. This mode of origin is strongly insisted on by Percivall, and no doubt occasionally arises. Under this explanation, however, it is difficult satisfactorily to account for its almost invariable occurrence on the left side. The mere fact that the horse is habitually approached on this side and more commonly turned toward it is a most insufficient reason.

Even if admitted it utterly fails to explain the immunity of the muscles supplied by the superior laryngeal nerve.

The fact that a horse has usually a hard and soft side of the mouth and carries the head slightly to the latter is no better explanation, as the tender side is not always the left.

More commonly the disease arises at some other point near the origin or in the course of the nerve, and the changes in the larynx follow as the consequence of deficiency or entire absence of motor innervation. Many cases can be cited in which such an origin was unquestionable, and on the hypothesis that this is the true and constant history of the development of the malady, its regular occurrence in the left side, and the absence of all signs of wasting in the muscles supplied by the superior laryngeal nerve are alike perfectly explainable.

Let it be noted that the vagus nerves (right and left) of which the recurrent laryngeal are branches, originate from the base of the brain, pass down the neck beneath the jugular vein in company with the carotid artery; that on entering the chest the right vagus nerve gives off its recurrent branch which proceeds at once up the neck along the course of its parent trunk till it reaches the larynx, to the muscles on the right side of which it is distributed; that the left vagus nerve on the other hand proceeds backward in company with the left innominate artery as far as the base of the heart, where on about the level of the space between the sixth and seventh ribs it gives off the left recurrent nerve; that this left recurrent nerve closely applied at its point of origin to the great parent arteries turns round the posterior aorta enclosing it in a loop, and gaining the lower end of the windpipe follows its course to the larynx. It will thus be understood how many chest diseases may implicate the left recurrent nerve, and from which the right, which extends no deeper than between the two first ribs, may be completely exempt. The frequent supervention of roaring as a sequel of chest diseases receives in this an ample explanation. Its connection with pleurisy becomes especially probable, as the nerve lies in contact with the surface of the pleura alike in its descending and ascending course within the chest.

Finally the loop encircling the posterior aorta exposes the nerve to constant stretching and shocks from the heart’s action during violent exertions and in excited states of the circulation generally. Vaerst and Sussdorf show that the nerve is habitually flattened between the posterior aorta and trachea, the effect being worst when the heart’s action is excited.

It remains to notice a few instances in which dissection established the connection of interference with the nerve at some part of its course and the existence of roaring.

(a.) Godine found in a roarer a tumor about the size of a chicken’s egg, pressing on the commencement of the pulmonary artery. He attributed the roaring to the impaired circulation of blood in the lungs by the pressure on the artery. Considering that the tumor must have been precisely in the situation of the left recurrent nerve at its point of origin, it becomes much more probable that the symptom resulted from pressure on this nerve.

(b.) The elder Bouley found in one case a considerable engorgement of the group of lymphatic glands in the anterior part of the chest and through the centre of which the left recurrent nerve passed.

(c.) Fergusson of Dublin dissected a roarer in which he found besides some tumors of the lymphatic glands in the pelvic and sublumbar regions, an indurated and enlarged gland about four inches behind the anterior opening of the thorax. The recurrent nerve between this and the larnyx was wasted so that its fibres could scarcely be recognized, the laryngeal muscles on that side were atrophied, and degenerated, and the glottis distorted and partly closed. Fergusson has in his description made the mistake of writing the _right_ for the _left_; it is evident that the _right recurrent nerve_ could not possibly pass through a tumor in the situation described.

(d.) Gamgee furnishes a drawing of an immense tumor filling up the anterior part of the chest, pressing on the vagi and recurrent nerves and causing roaring.

(e.) The Clinique of the Alfort Veterinary School furnishes the following among other cases of roaring consequent on inflammation of the jugular vein. A well-bred and very fast English thoroughbred had been used for two years by his owner who was a hard rider. In June, 1857, he was bled as a preventive (saignée de precaution), suppurative phlebitis was induced and was only cured at the end of six weeks. When again put to work he proved a _roarer_ and was still affected when seen six months later.

In connection with this it may be noted that the swelling in connection with the inflammation of the vein extends easily to the subjacent vagus and recurrent nerves, leading to their inflammation, functional inactivity and atrophy. Bleeding is usually done on the left side of the neck so that the paralysis and wasting would still be on the same side. Happily with a more humane system of treatment, accidents of this kind are less frequent than formerly. Glöckner furnishes a case which followed thrombosis of the carotid.

(f) Reynal reports several cases in which _roaring_ had occurred as a sequel of inflammations and abscess about the throat, and in which infiltrations or gray or yellow indurations had taken place in the areolar tissue around the vagus nerve. As nothing is more common than to find _roaring_ resulting from severe sore throat, parotitis, etc., this may explain its occurrence.

Mandl first carefully examined the paralyzed muscles which present to the naked eye a flattened and wasted appearance in marked contrast to the full well-rounded forms or those on the opposite side. They differ no less in color. In place of the deep red of the healthy muscles those on the diseased side are of a yellowish white hue with here and there a pink streak indicating the position of some unchanged muscular fibre. When placed under the microscope the healthy elements of the muscular fibres (sarcous elements) are seen to be replaced by granules of fat. The nerve (recurrent) is not only visibly wasted but its internal white substance (white substance of Schwann) can no longer be recognized and it approximates closely in character to a filament of ordinary white fibrous tissue.

17th. Muscular paralysis due to other causes and even located in different parts has been known to give rise to _roaring_.

Goubaux and others have noted the occurrence of roaring from paralysis of one nostril, alike when the loss of power was special to the nasal muscles or common to all on one side of the face.

Roaring apparently from paralysis of the laryngeal muscles has been seen frequently in animals fed on the seeds of leguminous plants and specially of the _Lathyrus Cicera_ (_Lathyrus Sativus Stendel_). The whole family of the _Leguminosæ_ is open to suspicion as occasionally containing a poisonous principle capable of inducing paralysis in animals fed on them. The _Lathyrus Sativus_ induces paralysis in man and the domestic animals in some parts of India (Sleeman, Irving). The common cultivated tare (Vicia Sativa) is well known to induce general paralysis, commencing with the hind extremities, when fed to horses at the period of ripening in Great Britain. In France the chick vetch (Lathyrus Cicera or Sativa) has been repeatedly noticed to lead to the development of roaring apparently from paralysis of the laryngeal muscles. Horses fed on 17 lbs, daily (straw and seeds) were attacked with roaring in five days. They gained in flesh and vigor, had a smooth shining coat and supple skin, and standing at rest presented nothing amiss, but after ten minutes trot they were seized with roaring and if not stopped they soon fell to the ground, with symptoms of impending suffocation, (Delafond). Horses fed heavily on the winter vetch with cut hay and molasses were attacked with roaring if gently exercised for one or two minutes. It came on suddenly and threatened instant suffocation. One horse fell and lay half an hour in a frightful state of dyspnœa. More commonly they recovered after a few minutes rest. In the intervals no disturbance of breathing nor any change of appetite attested the slightest deviation from health. Reynal, Cruzel, Caffin, Motte and Ayrault mention similar occurrences.

The paralysis of chronic lead poisoning will also cause roaring.

=Occasional or intermittent roaring.= Puzzling cases are met with in which a horse will _roar_ at one time and not at another. In such cases the veterinary profession has incurred an amount of odium which was by no means deserved. Two veterinarians, equally respectable and talented, appearing in a Court of Justice to swear to the same animal which they had examined on different days, respectively pronounce it a roarer or a sound horse, as it happened to be at the time of the respective examinations. Such cases have been differently accounted for.

Slight colds or _sore throats_ may cause roaring so long as they persist. Tight reining with the nose drawn in toward the chest induces a stridor in certain animals by distorting the larynx and trachea. Some horses with thick necks, badly set on heads, and in a state of obesity, roar, yet the symptom subsides when the superfluous fat is got rid of and they are brought into hard working condition. Stallions are very liable to make a noise from this cause. In a case of roaring which disappeared when the horse had been exercised for some time Leblanc diagnosed an œdema of the glottis which was absorbed under the increased movement of the parts. He did not test his opinion by dissection.

=Roaring sometimes hereditary.= That roaring runs in families there can be no doubt, but the direct cause appears to be mostly the transmission of a faulty conformation. A head with faulty shape and badly set on; a thick, short neck, deficient in mobility, or a small, narrow chest, predisposed to acute diseases, descends from parents to offspring, entailing a predisposition to roaring. The large Normandy horse is notoriously subject to roaring, but then he is equally characterized by a big, coarse head, narrow forehead and nostrils, big jowl, and narrow intermaxillary space. In all breeds this form is very subject to roaring, because of the stiffness of the neck and tendency to compression of the larynx. With the head badly set on, as it is almost of necessity in these animals, everything is done to produce roaring. Not only is the head cruelly reined in at work, but the horse is kept a great part of his time in the stable in the same or even in a worse condition, the larynx meanwhile unnaturally compressed between his narrow jaws and the nerve compressed or the larynx distorted.

It must be added, however, that like some other acquired distortions or alterations roaring may repeat itself in the progeny. Goodwin mentions an instance of it on the female side through three successive generations of thoroughbreds. Of transmission on the side of the male the following instance is noteworthy: M. Liphaert, an extensive proprietor in Livonia, bought a first-class English thoroughbred stallion. His progeny were healthy until he became a roarer at ten years old. All his foals, got after this date, followed the sire in becoming roarers, and, it is important to observe, almost all at the age of ten years.

_Symptoms._ These, of course, are manifest enough while the animal is sufficiently excited to give rise to the noise. Certain indications may be obtained even while the animal stands in the stable. If _cough_ is excited by pinching the upper rings of the windpipe it is prolonged into a groan. If suddenly threatened with a cane the abrupt inspiration which results is attended by a _grunt_. The absence of these symptoms is not, however, sufficient to establish the nonexistence of roaring. The horse must be galloped or put to heavy draught to fully test the breathing organs. Galloping up a steep hill is perhaps the best test. A gallop over a recently ploughed field is about equally good. Soft pasture land or an unpaved road is preferable to Macadam or pavement. Galloping in a riding school on the soft tan is an excellent measure as the sound is confined and the animal is always within earshot of the examiner. The person examining should either ride the horse himself or have a disinterested party, in no way connected with either buyer or seller, to mount him. If the rider is in the interest of the seller he may contrive to slacken the pace before he reaches the examiner, or by irritating the horse may make it difficult to approach him immediately on his being pulled up. If in the interest of the buyer he may succeed, by the use of a powerful bit, in drawing the horse’s nose in to the chest, or by compressing the larynx with a tight throat latch he may produce noise in breathing when the animal is suddenly brought to a stand. Unless the course is up a steep hill or over a ploughed field the horse should be galloped for from five to ten minutes; he should be then made to pass close to the examiner at full speed, and finally brought up suddenly by his side and without any previous slacking of his pace. The ear should be at once placed close to the nostrils, when the slightest abnormal sound accompanying the inspiratory act will be at once recognized.

Draught horses are sufficiently tested by driving them in a heavy vehicle or one with the wheels dragged. By walking alongside or keeping the ear near to the nostrils any harsh sound additional to the normal blowing noise of hurried breathing is easily noted.

The finger placed on the larynx detects the strong vibratory tremor, and Friedberger notes that the left arytenoid is much more easily displaced than the right, increasing the stridor.

If the horse is, at the time of examination, the subject of a cold, sore throat, or other acute disease of the air passages no importance is to be attached to any noise made in breathing, but he cannot be pronounced a _sound_ horse until, this malady having passed off, it is found on careful examination that no such sequel has been left.

Among the most puzzling cases are those in which the roaring occurs with periods of intermission. If the horse has been fed for a short time on vetches this may account for its temporary access, and unless the same feeding is again allowed a recurrence is not to be looked for. If due to the occasional displacement of a pedunculated tumor of the nose or pharynx and its interference with the action of the larynx its existence may be recognized by careful examination, diminished current of air through one nostril, etc. But there remain some _rare_ cases in which there are no such appreciable causes, and yet the horse would be pronounced _sound_ or _unsound_ as examined at certain intervals. On this subject more information is desirable.

The following varieties of roaring will be distinguished from that of paralysis by the occurrence of the sound in both acts of breathing (expiration and inspiration):—distortions, tumors or foreign bodies in the nose:—tumors about the throat, in the windpipe or bronchi:—distortion of the windpipe, from tight reining, fracture or congenital deformity:—and the presence of a false membrane stretching across the windpipe.

Examination by manipulation, auscultation and percussion along the whole length of the air passages alike during rest and after exercise, may enable one in unusual cases to recognize the structural changes that give rise to roaring.

_Treatment._ This has long been considered as hopeless, yet preservative and palliative measures are usually accessible, whilst even cures can be effected in certain conditions.

_Preventive treatment._ First may be noticed the rejection for breeding purposes of all animals possessing those conformations of head, neck and chest already referred to as conducing to disease of the air passages or distortion of the larynx or windpipe. Equally ought all roarers to be set aside unless the exciting cause is accidental such as fractures of the nasal bones, of the trachea, the existence of polypi, etc. Stallions that make a harsh noise in breathing from an accumulation of fat about the throat are not necessarily objectionable.

The employment of the bearing rein so as to compress and distort the larynx is to be avoided. If bearing reins are used in horses having short thick necks and badly set on heads and especially with intermaxillary narrowness they should be passed through rings in the cheek piece of the bridle or between the ears and over the forehead (overdraw check) so that while the head is elevated the nose may be projected forward after the Russian fashion of equitation. This measure has indeed appeared to cure several cases of roaring. I have met with fewer roarers in the same number of horses in America than in England, and this I attribute to the better mode of using the bearing rein on this side of the Atlantic.

The Chick Vetch (Lathyrus Cicera) should be excluded from the fodder of horses or used in small proportion only. In man it is found to be injurious when it forms a twelfth part of the bread used and gives rise to paralysis if it amounts to a third (Aitken).

_Palliative and Curative treatment._ Medicinal treatment will prove useless in the great majority of cases: as for example in paralysis and degeneration of the muscles, in ossifications, fractures, or distortions of the cartilages, etc., etc. Nevertheless where there is merely thickening of the membrane of the larynx alterative and tonic treatment may be successful especially if associated with iodine ointment or active blisters applied to the throat. A case is reported by Dupuy in which a course of arsenic cured. In these cases as well as in those due to ulceration of the membrane the application of caustic by means of a staff and sponge as advised in laryngitis may prove beneficial. In some cases of this kind the application of the firing iron to the region of the larynx has an excellent effect. Setons have proved useful in some cases.

In cases due to tumors or enlarged glands pressing on the air passages the internal use of iodine and other alteratives and diuretics, and the local applications of iodine, or mercurial ointments or of blisters have been successful. Failing in this the tumors may be removed with the knife when accessible.

If by auscultation the existence and position of a band of lymph can be made out, tracheotomy may be performed and the band excised. Percivall with reason doubts the possibility of the diagnosis.

In cases due to distortion of the larynx from tight reining the bearing reins should be dispensed with or rearranged so as to encourage protrusion of the nose, and the horse should be bitted to the side chains or straps in the stall several hours daily so that the head shall be elevated and the nose protruded.

When _roaring_ depends on paralysis of the laryngeal muscles, a mode of palliation may be adopted as practised by the London omnibus and cab men. A strap is fixed round the nose supported by a strap passing down the middle of the face and the cheek piece of the bridle on each side and buckled beneath the chin. On the inner side of this strap where it passes over the false nostrils is attached on each side a semiovoid pad which presses on the flap of the nostril and regulates the entrance of air. The principle on which it acts will be understood when we consider that the paralyzed cartilage is drawn into the passage by the rush of air and that the closure of the channel is more complete and the roaring more marked in proportion to the force of the current. The pads by lessening and regulating the rush of air into the lungs thus leave the passage in reality more open and largely obviate the difficulty of breathing and the noise.

In extreme cases with the structural lesion in the head, throat, or upper two-thirds of the neck relief may be secured by tracheotomy.

A more radical operation is that introduced by Günther for the excision of the left arytenoid cartilage. As improved by Möller and others this consists in an incision through the cricoid cartilage and crico-thyroid membrane (or even the first rings of the trachea) and the complete extirpation of the left arytenoid cartilage and left vocal cord. The manipulations belong to surgery. The result is satisfactory in removing the violent dyspnœa in hurried breathing and in very favorable cases in obviating noise altogether. More commonly some stridor remains but not enough to interfere with pace or with heavy draft. From my personal experience in performing the operation, I would recommend it in all cases in which the obstruction is so great as to interfere with the use of the horse on the track, or road, or for heavy draught. But in slight cases, in which the disease causes little or no inconvenience beside the noise, I would advise some less radical measure.

Another obvious line of treatment is by the use of electricity locally and of strychnine internally. A weak current kept up for fifteen minutes may be sent from the positive pole in the left jugular furrow to the negative pole over the left side of the larnyx. Strychnia in the dose of two grains may be given daily in the food or in half that amount hypodermically over the left side of the larnyx. This would be useful only in the early stages with little or no fatty degeneration of the muscles.

ŒDEMA GLOTTIDIS.

Diseases Complicated by this. Seat, Abundance. Duration, Sequels,
Symptoms, sudden dyspnœa, swelling of throat, pits on pressure,
differentiation from croup. Treatment, cold, ice, astringents,
scarification, tracheotomy.

This is usually a complication of acute laryngitis, but it may be a manifestation of other forms of local disease—tuberculosis, glanders, purpura hemorrhagica, pseudo-membranous inflammation,—or it may be a result of a more distant affection, like disease of the heart, lungs, or kidneys. As a complication of local inflammation it consists in an excessive serous exudation into the submucosa, around the base of the epiglottis and extending to the whole larnyx and pharnyx. It may thicken the parts by half an inch, causing complete closure of the glottis. In favorable cases it may subside as rapidly as it rose, while in others it may result in ulceration or abscess. The infiltration has usually a clear watery aspect, but is sometimes a dull red. When incised an abundance of serum escapes mixed in certain cases with pus.

_Symptoms._ In the course of one of the above named affections there comes on suddenly extreme dyspnœa, with stertorous breathing, a suffocative cough, and intense anxiety. The stridor is first with inspiration and later with expiration as well. The eyes are bloodshot and protruding, the pulse small and rapid, the movements uncertain, and the skin moist with sweat. There is manifest swelling of the throat and manipulation leaves the imprint of the finger.

When symptomatic of some distant affection it is at once slower in its result and more persistent.

The local pasty swelling and the absence of any false membrane suffice usually to distinguish it from croup which it so closely resembles in the suddenness of its onset, and the violence of its manifestations.