Chapter VII: Part 7

14th. Sulphate of Lead is a by product in the preparation of acetate of aluminium for dyeing.

_Forms._ Lead poisoning occurs in acute and chronic forms. The two forms, however, merge into each other and are largely convulsive and paralytic.

_Experimentally._ Harnack found that 2 to 3 mgrms. in frogs and 40 mgrms. in rabbits caused increased intestinal peristalsis, diarrhœa, and paralysis of the heart. Dogs had choreic symptoms. Gusserno gave 1.2 grm. to rabbits and dogs respectively, and produced emaciation, shivering and paralysis of the hind extremities. Rosenstein with 0.2 to 0.5 grm. obtained in dogs similar symptoms with epileptiform convulsions, and Heubel had symptoms of colic in a few cases.

=Casual or Accidental Poisoning.= Metallic lead is slowly dissolved and therefore large doses of this may be taken in without visible ill effect. Shot has often been given to relieve the symptoms of broken wind in horses, and a dog at the Lyons Veterinary School took four ounces without visible ill effect. When finely divided, however, as in sheet lead or the spray of bullets it presents a much more extended surface to oxygen and acids, and in the acid stomach of monogastric animals, or even in the organic acids of the rumen it is dissolved in quantity sufficient to prove poisonous.

_Symptoms in Horses._ Shenton thus describes his cases. “There was a rough, staring coat, a tucked up appearance of the abdomen, and a slightly accelerated pulse; in fact, symptoms of febrile excitement which usually, however, passed away in about a week. About this time large quantities of gray colored matter were discharged from the nostrils, and saliva from the mouth, but at no time was there any enlargement of the submaxillary, lymphatic, or salivary glands. Nor was there constipation of the bowels, which appears to be nearly always present in cases of lead poisoning in man. Fits and partial paralysis came on at intervals; and when the animals got down they often struggled, for a long time ineffectually, to get up again. The breathing up to this time was pretty tranquil, but now became so difficult and labored that the patient appeared in danger of suffocation. The pulse was in no case above 60 or 70, and I ascribe the difficulty of respiration to a paralyzed state of the respiratory apparatus. The animals did not live more than two or three days after these symptoms appeared. The _post mortem_ appearance varied but little. The lungs and trachea were inflamed; the lungs engorged with large quantities of black blood; the trachea and bronchia filled with frothy spume. In all cases but two the villous part of the stomach presented isolated patches of increased vascular action, and in all cases the intestines, and especially the large ones, were inflamed. The blind pouch of the cæcum was nearly gangrenous. There was nothing remarkable about the liver, spleen or kidneys, except that they were of a singularly blue appearance.”

_Symptoms in Ruminants._ These are described by Herapath as following the erection of lead smelting furnaces in the Mendip Hills in Somersetshire. There were stunted growth, emaciation, shortness of breathing, paralysis of the extremities, particularly the hinder ones, the flexor muscles of the fore limbs affected so that the animals stood on their toes, swelling of the knees and death in a few months. Even if removed to a healthy locality the victims failed to thrive. The effects were most pronounced in the young. Lambs were born paralytic; at three weeks old they could not stand, and palsy of the glottis rendered it dangerous to feed from a bottle. Twenty-one out of twenty-three died early. The milk of cows and sheep was reduced in quantity and quality, and contained traces of lead. The cheese had less fat in it. The dead showed the mucous surfaces paler than natural and the lungs had large areas with abruptly circumscribed margins of a dark red color, surcharged with fluid. A blue line appeared on the gum close to the teeth, and from this a globule of lead could be melted under the blowpipe.

In the cases that have come under my observation paralysis of the hind limbs, emaciation and low condition, have been most prominent in the chronic forms, while these have been complicated by torpor of the bowels, blindness, stupor, coma, and more or less frequent paroxysms of delirious excitement or convulsions in the acute. In the chronic cases the blue line on the gums is an important symptom.

Herapath noticed that near the smelting furnaces pigs escaped if kept in the pen but suffered if allowed to go at large. This is explained by the presence of lead in the forms of oxide, carbonate and sulphate on the herbage, hay and hedge rows, and in short, on all vegetation.

In _post mortem_ examination the stomach should be carefully searched for lead in the metallic form as sheet lead, bullet spray, etc., for the different forms of paint of which lead forms an ingredient, for the discarded white lead packing of pipes and machinery, and even for solid masses of metallic lead. This is especially necessary in the case of cattle in which the morbid habit of eating non-alimentary matters is so common, and for which the sweet taste of some of the lead compounds seems to offer an attraction. The lead being long retained in the first three stomachs in contact with acetic and other organic acids is especially liable to be dissolved and absorbed in dangerous amount.

In the chronic cases especially, the test by electric current may furnish a valuable pointer. In lead poisoning the muscles respond much less actively to the stimulus than in the normal condition.

In resorting to analysis the following table from Heubel of the amount of lead in the different organs of a dog may offer a guide to the selection of an organ for examination:

Liver .03 to .10 per cent.
Kidney .03 to .07 „ „
Brain .02 to .05 „ „
Bones .01 to .04 „ „
Muscles .004 to .008 „ „

Professor George Wilson found the lead very abundant in the spleen, and used it for analysis. He dissolved it in aqua regia over a slow fire, cooled, filtered, evaporated, cleared, and boiled with dilute nitric acid. Then filtered and dried again, dissolved in dilute muriatic acid, and finally applied the color tests. With hydrosulphuric acid it gives a black precipitate, with sulphuric acid, a white, and with potassium iodide or bichromate a bright yellow. Or from the solution of the chloride the lead may be obtained as a metallic deposit on zinc from which it can be fused into a minute globule on charcoal.

In the _treatment_ of lead poisoning the first object is to prevent the further solution of lead in the alimentary canal and to carry it off. To fill the first indication, hydrosulphuric acid or sulphuric acid may be administered to form respectively the insoluble sulphide or sulphate. As a purgative, sulphate of magnesia or soda should be preferred, as favoring at once elimination and the formation of an insoluble precipitate. Large doses are usually desirable, especially in ruminants, because of the bulky contents of the stomach and the torpor of the alimentary canal. If griping is a prominent symptom opium or other antispasmodic must be added.

In chronic cases, after the evacuation of the contents of the alimentary canal small daily doses of potassium iodide will serve to dissolve the lead out of the tissues, while sulphates may be given in small doses to assist in elimination from the bowels and to prevent reabsorption. The treatment by potassium iodide is equally applicable, to assist in the elimination of the lead that has passed into the circulation and tissues. The doses, however, should in any case be small to avoid the sudden solution of a large amount of lead which had been deposited in the tissues in a comparatively insoluble form. The sudden entrance into the circulation of any large amount of such lead would induce a prompt return of the toxic symptoms. A continuous exhibition of small doses is the course of wisdom and safety. The bowels should meanwhile be kept somewhat relaxed by small doses of sodium or magnesium sulphate. As a general tonic a course of bitters may be called for, especially when torpor or emaciation is pronounced.

ALCOHOLIC INTOXICATION.

Beer in pigs, alcohol in dogs, absinthe in horse, alcohol and burnt
ales in cows, alcoholized grain in fowls, also fermented raisins.
Symptoms, lack of coördination, staggering, flushed mucosæ, full
pulse, stertor, sopor, coma, alcoholic breath, chill, muscular
twitching, delirium. Treatment: ammonia acetate, or carbonate,
apomorphia, pilocarpin, warm water, coffee, stomach pump, electricity.

Poisoning by alcohol is less common in the lower animals than in man, yet the veterinary journals record a considerable number of cases. We have seen pigs suffer from drinking soured beer; the smaller breeds of dogs (English terriers) which are systematically dwarfed by feeding alcohol are often kept for a length of time in a condition of semi-intoxication. Bissauge records the case of a horse inebriated by a glass of absinthe and a pint of white wine, and that of a cow which died intoxicated 24 hours after she had been given three quarts of pure alcohol (Rec. de Med. Vet. 1895). Dundas records intoxication in cows fed on _burnt ales_. Intoxication of barnyard fowl and wild birds from eating grain soaked in strong alcoholic liquids has been frequently noticed, and Bissauge reports fatal drunkenness among our domestic fowls from eating raisins and other fruits which had undergone fermentation.

The _symptoms_ are too suggestive to require notice in detail. There is a lack of coördination of movement, a staggering gait, a disposition to lie, dilated pupils, dark red flushing of the visible mucous membranes, a full pulse, stertorous respirations, drowsiness, stupor, and finally coma. The breath exhales the odor of alcohol, and the temperature usually falls, especially if the subject has been exposed to cold. It may rise later in connection with inflammation of the stomach or brain. Muscular twitchings and delirium are sometimes found, and may occur paroxysmally.

_Treatment._ A pint of liquor of the acetate of ammonia to horse or ox may quickly relieve the symptoms, or 1 oz. carbonate of ammonia may be given in solution in a pint of vinegar. If more convenient the hypodermic injection of 1 or 2 grains of apomorphia, or of 5 grains of pilocarpin may be employed. Warm water is of the greatest value in securing elimination. A strong infusion of coffee is very effectual. If the patient is a vomiting animal an emetic may be employed, and in case of coma the stomach pump may be resorted to. Cold applied to the head or galvanism may be used to rouse the patient.

In case of gastritis or encephalitis following the attack these must be treated according to indication.

ANILINE POISONING.

Composition. Source. Uses. Toxic action on skin, by inhalation, and by
stomach. Symptoms: acute: chronic. Test. Treatment: emesis,
purgatives, stimulants, tonics, enemata, bleeding, normal salt
solution.

Aniline (Amidobenzene, Phenylamine, C_{6}H_{7}N) is a product of coal tar produced in the manufacture of benzole and of aniline dyes. Being an object of large production and consumption in the arts, its toxic action is seen not infrequently in man, and less so in animals. As used in confectionery it is so diluted that it is rarely or never injurious. On textile fabrics, however, it often causes cutaneous irritation, and when eaten by animals may be toxic. Workmen in the factories usually suffer from its inhalation.

Turnbull gave ½ dram sulphate of aniline to a dog, inducing vomiting in 2½ hours and purging one hour later. There were accelerated pulse, labored breathing and paraplegia, followed by recovery in five hours. Other objective symptoms are coldness of the surface, and a bluish or purple color of the visible mucosæ, the blood failing to take up oxygen. In chronic aniline poisoning in man the following symptoms have appeared: papular, vesicular or pustular skin eruptions, or ulcers on hands feet and scrotum; an odor of coal tar; anorexia, nausea and vomiting; headache, vertigo, stupor, ringing of the ears, amblyopia, muscular spasms, muscular weakness, anæsthesia and motor paralysis especially of the extremities. The fatal dose is 1½ dr. and upward.

Aniline may be extracted from the tissues by petroleum ether, and on the evaporation of the solution, it is left as an oily yellowish mass which gives the following reactions:—with a few drops of sodic hypochlorite a blue or violet blue; with acids a rose red; with bromine a flesh red.

The _treatment_ must be by elimination by emesis, or purgation, by removal from aniline fumes or mixtures, and by stimulating and tonic agents. In place of emesis a stomach tube and lukewarm water in large amount may be employed to wash out the stomach. For vomiting animals ipecacuan may be employed. Copious enemata may be given, along with purgatives, to clear out the bowels. As stimulants strong coffee, caffein, camphor, or strychnia may be employed. In case of profound stupor, prostration, or paresis it may be desirable to reduce the amount of aniline in the system by free bloodletting, care being taken to inject subcutem, or into a serous cavity, a nearly equivalent amount of normal salt solution.

POISONING BY NITRO-BENZOL.

Composition. Source. Uses. Characters. Toxic qualities. Convulsions:
paralysis: cyanosis; weak pulse; bitter almond odor; dark red urine;
sopor, giddiness; reduced size of red blood globules; congested brain,
stomach, intestines. Treatment: emesis, purgation, stimulants,
electricity, derivatives, bleeding, normal salt solution.

Nitro-benzol (Nitro-benzine, C_{6}H_{5}NO_{2}) is a coal tar product, formed in large quantities in the manufacture of aniline dyes and extensively used as a flavoring agent for soaps, sweet meats, etc. It is formed by the addition of strong nitric acid to benzine, and appears as a yellow fluid with an odor resembling, yet somewhat different from, that of prussic acid or oil of bitter almonds. It may prove deadly to man or dog in a dose of fifteen drops, though most commonly it enters the system by inhalation. In animals the prominent symptoms are convulsions and paralysis, supervening on a period of weak circulation and pulse, and blueness of the visible mucous membranes. The characteristic odor resembling the oil of bitter almonds exhales from the lungs and skin. In man there are dilatation of the pupils, blueness of the lips and nails, pallor of the face, weak pulse, slow breathing (often in the end Cheyne-Stokes respiration), a dark maroon or port wine color of the urine, and amblyopia. In the chronic cases the skin is yellowish, and there are weariness, a dragging walk, headache, morning anorexia, drowsiness, giddiness, numbness of the hands or other parts and emaciation. The blood is chocolate color with red globules reduced in size, in number and in hæmoglobin, but containing an excess of carbon dioxide. The brain is often congested and the gastro-intestinal mucosa like the skin may be yellow (from alleged formation of picric acid). In chronic cases disseminated sclerosis may be seen.

In _treatment_ emesis, purgation, stimulants (ammonia, camphor), galvanism, sinapisms to the chest, and phlebotomy, with injection of normal salt solution, may be resorted to, as in aniline poisoning.

POISONING BY CARBON DISULPHIDE.

Used to kill insects in grain, etc., in barns. Locally anæsthetic, and
irritant. Inhaled, toxic, causing excitement, anæsthesia, collapse.
Large doses, excitement, reckless movements, incoördination,
giddiness, sleep, stertor, paraplegia. Small doses, weakness,
emaciation, tremors, paraplegia, polyuria, mellituria; convulsions,
death. Distortion and varicosity of axis cylinder, and unequal
staining of cytoplasm. Treatment: pure air, good diet; massage,
electricity, tonics, phosphorous.

This agent is largely used in vulcanizing and other factories where the employes are liable to suffer, and also in granaries, barns, etc., for the destruction of insects in grain and other objects and where animals are liable to suffer.

_Locally_ it acts like chloroform, when confined to the surface, as under a glass or covering, producing very active irritation with anæsthesia.

_Inhaled_ it produces intoxication, excitement, general anæsthesia and finally collapse. In rabbits it causes intense excitement, giddiness, swaying from side to side, and reckless leaps forward, followed by profound sleep with deep stertor, and paraplegia for half an hour after the return of consciousness (Oliver). When taken for a long time in smaller quantity it caused weakness, emaciation, tremors, paraplegia, and death in convulsions. There was polyuria, with excess of sugar but neither urea nor albumin. The large cells in the motor areas of the brain, when stained by Golgi’s method, showed the axis cylinder distorted and varicose, and the cytoplasm stained unequally. The action on dogs was essentially the same, and in neither animal were changes in the blood globules observed (Oliver).

In man slow poisoning caused headache and exhilarate intoxication, followed by depression, mental apathy, dullness, loss of memory, impaired vision, hearing, sexual desire and muscular power. Cramps are common (Delpech, Curtis).

_Treatment_ consists in giving pure air, good food, massage, galvanism, tonics, and for the persistent nervous failure phosphorus.

TETANY.

Definition. Casual and experimental cases in animals. Causes: Excision
of the thyroid, indigestions with fermentation, rheumatism, infection,
malaria, rachitis, want of hygiene, hereditary or developmental
irritability, microbian poisons. Symptoms: intermittent spasms with
semi-flexed limbs, tremors. Diagnosis: by the complete intermissions
of spasms, and by pressure on nerve or artery, rousing them. No fever.
Like spasms of ergot. Treatment: thyroid extract, grafting thyroid;
remove sources of irritation, antispasmodics, warm or tepid baths,
electricity.

_Definition._ Tetany is the name given to a limited contraction of a group of muscles usually in the extremities occurring paroxysmally with intervals, during which it may usually be roused into activity by compression of the nerve or artery proceeding to the muscles in question.

The disease has not been accorded a place in systematic works on veterinary medicine, though cases have been recorded which are supposed to have been of this nature, and in cases occurring in man and associated with dyspepsia and gastric dilation, Bouveret and Devic have extracted from the contents of the stomach a toxic substance which caused tetanic convulsions in animals. The total removal of the thyroid gland, or even of four-fifths of it (Eiselsberg), in the cat is found to be invariably followed by tetany.

_Causes._ Beside the origin from the removal or general disease or degeneration of the thyroid, it has been attributed to digestive troubles, associated with fermentations and the production of toxic matters, to rheumatism, infection and malaria, to rachitis and unhygienic conditions. The systemic changes and trials of growth and development, of pregnancy and lactation, seem to be factors in certain cases. A peculiar irritable nervous organization transmitted by heredity is undoubtedly a potent cause, and upon this, bacteridian, leucocytic and other poisons operate so as to rouse the paroxysms.

_Symptoms._ There are usually prodromata in the shape of dullness, prostration, weariness, and some dullness of the special senses. Fever is commonly absent and the contractions tend to affect both flexors and extensors, but as the force of the first predominates, the affected member is usually held more or less rigidly semi-flexed. The spasm appears suddenly, often taking occasion of some voluntary movement, and may last for several minutes or hours. It is followed by an interval of relaxation of equally uncertain duration. Though usually attacking the limbs and causing the victim to walk on the toes, it may extend to the face, neck or trunk, and constitute an intermittent trismus, oposthotonos, or emprosthotonos.

_Diagnosis._ Tetany is to be distinguished from tetanus by the complete intermissions of the spasms, and by the voluntary development of these by compression of the presiding nerve or artery. Pressure on the nerve arouses its excitability, and compression of the artery shutting off the supply of blood from the disordered and susceptible muscles, tends to increase their irritability. Ligature of an artery supplying healthy muscles causes simple trembling of such organs. From the spasms of cerebral, spinal or meningeal inflammation tetany is distinguished by the absence of fever, and the complete intermissions of the paroxysms. The spasms of ergotism bear the closest relation to those of tetany and in the absence of proof of the ingestion of ergot, might well be confounded with them.

_Treatment._ This consists mainly in doing away with the causes, when these can be ascertained. Portions of thyroid may be grafted if complete thyroidectomy has been performed, or thyroid extract may be given. In the human subject recoveries have followed the expulsion of intestinal worms, the cure of gastric dilation, dyspepsia, fermentations, diarrhœa, rachitis, menstrual irregularity, or auto-intoxication. Fíré has seen recovery follow the extraction of a carious tooth.

The spasms may be met by the internal administration of antispasmodics (chloral, belladonna, bromides, opiates), and the external application over the affected muscles of anodynes and antispasmodics (belladonna, opium, chloroform, oil of cajeput, oil of peppermint, menthol, etc.). Warm or tepid baths are often of great value and a mild electric current has been found useful.

CONGESTION OF THE SPINAL CORD IN THE HORSE AND COW.

Under this heading Trasbot describes hæmoglobinuria and parturition paresis, but this tends to cover up the more important causes and phenomena of these diseases, which should be kept in the foreground. Spinal congestion is undoubtedly a feature of both these affections, and the sudden onset and rapid recoveries often seen, indicate the absence of inflammatory action, yet this is but an accompaniment of a constitutional morbid state which we think fully warrants a special consideration of each elsewhere (see Hæmoglobinuria; Parturition paresis).

Apart from these affections congestion habitually merges into myelitis or spinal meningitis, and may be considered as the initial stage of these disorders. It owns the same causes and is manifested by closely allied symptoms, but these are less persistent, and may subside abruptly into a condition of health. The treatment will be on the same general lines as for myelitis, but with much better hope of success.

ACUTE MYELITIS. POLIOMYELITIS. INFLAMMATION OF THE SPINAL CORD.

Causes: Stimulating food to excess, sexual over-stimulation, violent
overexertion, hot sun, chill, rheumatism, traumas, injury to spinal
nerves, vertebral caries, microbian infection, narcotics, vegetable
poisons, cryptogams. Lesions: discoloration of white or gray matter,
swelling, friability, softening, extravasations in points, leucocytes
in excess, nerve cells cloudy, granular, nucleus enlarged, stain
highly, chromophile granules irregular, neuroglia thickened. Symptoms:
Hyperthermia, rigor, hyperæsthesia, tonic contractions in neck and
limbs, intense lameness, paresis, palsy, muscular atrophy, areas of
heat followed by coldness, such parts may not perspire, palsy less
complete than in broken back, circulation and breathing accelerated or
slow, paraplegia in large herbivora. Diagnosis: progressive onset,
hyperæsthesia or rigidity merging into palsy, retention and later
incontinence of urine, extreme spinal tenderness, rapid atrophy of
affected muscles, skin sloughing. Prognosis, always grave. Treatment:
purgation, bleeding, hot fomentations, ice bags, compresses,
derivatives, bromides, chloral, potassium iodide, atropia, ergot,
electricity, strychnia, soft laxative food, bitters, phosphates.

_Causes._ Like congestion this may be a result of =plethora= in overfed animals, in those subjected to specially stimulating food like gluten meal, cotton seed meal, beans, peas, vetches in excess, animal food for herbivora (the waste of hotels and restaurants for cows, compressed meat products for pigs), a period of absolute rest on full rations in horses habituated to hard work and full feeding; of =sexual over-stimulation= in males (stallion, bull, ram); of =violent overexertion=, especially if =under a hot sun=; of =sudden chill= when over-fatigued and perspiring; of =cold rain storms= (Freirier); of =rheumatism= (Kowalski); of =traumatism= (fractures, sprains, slipping with overdistension); of =falls upon the point of the ischium=; of blows upon the back (Cruzel, Trasbot); of =tumors implicating the cord=; of =too violent efforts in serving= by stallions; of =injuries of the great nerve trunks= passing off from the cord (Gull, Trasbot, etc.); of extensions from =caries or suppurations of the vertebræ= (Decoste, Trasbot); of =microbian infection=, as in rabies, distemper, tubercle, dourine, louping ill, milk sickness, contagious pneumonia, influenza, and suppurations; of =narcotic poisoning=, as from ergot, smut, the poisons of the cryptogams and bacteria of mouldy bread, musty fodder, spoiled meats, fish, etc.; also the poisons of =lolium=, =vetch=, =lupin=, =astragalus=, =oxytropis=, =arsenic=, etc.

_Lesions._ These consist in a yellow or pink discoloration of the white and especially of the gray matter, and a special prominence of the puncta vasculosa in the affected part. Swelling or distortion of the part is not usual. This may involve only a single gray horn, the two horns on the same side, the two inferior horns, or all four at once, or the white matter adjacent may also show the rosy tint, the large puncta, and a characteristic softness and friability. Minute blood extravasations are very significant. Microscopically examined leucocytes are found in abundance in the perivascular spaces and in the neuroglia. The neurons (nerve ganglion cells) are degenerated, being cloudy, swollen, with enlarged nucleus, stain highly, and show enlargement of the chromophile granules. In a more advanced stage the cell has an indefinite outline and the nucleus is indistinct and may fail to take a stain; the chromophile granules are irregular and do not radiate evenly from a centre and many vacuoles appear. This may lead to fatty softening, or to fibrous increase of the neuroglia, and sclerosis.

_Symptoms._ These vary greatly in different cases according to the part involved, the meninges or some special region of the cord, to the essential cause of the inflammation and its acuteness. Usually the attack sets in slowly in contradistinction to the abrupt attack of congestion. =Hyperthermia= and =rigor= are usually among the first symptoms, though in many cases =hyperæsthesia= is the most marked early symptom. The skin covering the muscles which derive innervation from the affected section of the cord is the most sensitive. This is often so extreme along the vertebral column that percussion on the spinous processes or pinching between the fingers and thumb causes the most pronounced wincing and dropping of the back. Copland and Laposso have noticed that a sponge of hot water drawn along the line of the vertebræ causes acute pain and contractions of the muscles of the back and limbs, which are almost tetanic in their force. This probably implies the existence of meningitis, since the absence of rigidity of the muscles of the neck, back and limbs, usually implies the absence of meningeal inflammation. It may, however, occur in localized or commencing myelitis. The existence of unilateral lesions and rigidity determines intense lameness, which is further characterized by the most marked hyperæsthesia.

The =morbid phenomena of the motor system= are more characteristically paretic or paralytic than spasmodic. When rigidity or spasm ushers in the attack it is superseded in a few hours or in two or three days by flaccidity of the muscles of the affected part, with imperfect control or even complete paralysis. The muscles affected will depend on the seat of the spinal lesion. If in the neck it may affect fore and hind limbs, and even the chest and abdomen; if in the back or loins it will induce paraplegia, the anterior limit of which will correspond to the seat of the lesion; if near the caudal extremity of the cord, (lumbar portion), paralysis of the tail and of the sphincters ani and vesicæ may be prominent features. Retention of urine and fæces (spasm) may precede incontinence (palsy).

=Common sensation= may be dull or abolished on one or on both sides. If on one side only, the other may show hyperæsthesia.

=Trophic modifications= are very marked though they may not be noticeable at first. The paralytic muscles waste rapidly and the impaired nutrition is manifested in the rapid formation of sloughing and intractable sores where pressure comes in recumbency (the hips, stifles, hocks, shoulders, etc.). This is especially noticeable on parts supplied by the cord at or behind the seat of the lesions.

=Vaso-motor changes= are usually marked by a preliminary hyperthermia of the affected parts, followed by a corresponding hypothermia. Sometimes the affected part of the skin will remain quite dry while the rest of the body is covered by perspiration.

=Choked optic disc= and retinitis are sometimes present.

The =febrile reaction= which is at first moderate, gradually increases in force; the animals become dull, drowsy, careless of food, and the hyperæsthesia merges into paresis or paralysis. This is rarely so complete as in fracture of the vertebræ. If the inflammation is restricted to the lower columns only, there may be akinesis without change of the sensitiveness or with hypersensitiveness. If restricted to the upper columns there may be sensory paralysis only on the opposite side.

The =heart sounds and pulse= are usually altered, palpitations may appear early with acceleration and sharpness of the pulse, and this may alternate with a tardy slow pulse with intermissions. =Breathing= also becomes accelerated and in violent cases with trembling, though in moderate inflammation with effusion, softening and degeneration, it is liable like the heart beats to become slow and tardy.

When =vertigo= appears it may be attributed to extension to the bulb or cerebellum, or to the sympathetic implication of these organs.

The frequency with which paraplegia occurs in the large herbivora suggests a special susceptibility of the lumbar portion of the cord, probably in connection with severe muscular effort of the hind limbs.

In protracted cases the fever may run very high, being complicated by septic poisoning from the numerous cutaneous sloughs and sores, as well as by cystitis and nephritis.

_Diagnosis._ This may be based on the progressive onset, unlike the sudden attack of congestion; on the occurrence of primary fever with hyperæsthesia or even muscular rigidity, merging into a later paresis or paralysis; on the retention of urine, followed by incontinence; on the torpor of the rectum; on the extreme tenderness of the spine in the region of the inflammatory lesion; and on the tendency to rapid atrophy of the affected muscles, and the death and sloughing of the skin under pressure over the prominent parts of the body. The definite localization of the muscular symptoms, and the different temperature and secretion of the affected part of the skin, from the unaffected, are further confirmatory of myelitis.

_Prognosis._ While always grave, myelitis induced by narcotic elements in the food which can quickly be eliminated from the system, and that which has not caused compulsory decubitus, or persistent retention of urine and fæces, may be considered as hopeful. When, on the other hand, the nature and extent of the lesions have entailed a prolonged paralysis, or in the large animals, (especially solipeds), a persistently recumbent position, there is little to be hoped for. The degenerated myel, and the badly wasted muscles, combine to prevent rising and the use of the limbs, the sloughing bed sores quickly poison the blood and general system, and the animal sinks beyond hope of remedy. Again, if the fæces accumulate in the rectum causing general retention of the bowel contents and fermentation, the shock to the nervous system and the toxins absorbed add materially to the prostration and danger. Finally the retained urine infected through the blood or by a catheter, quickly passes into ammoniacal fermentation, with softening and detachment of the cystic epithelium, septic infection of the mucosa, and the extension of this infection through the ureters of the kidneys. The complication of infective inflammation of bladder and kidneys introduces one of the most dangerous conditions possible.

_Treatment._ In an acute case, at the outset, elimination of any extraneous poison should be sought as the first step toward a restoration of the normal spinal functions. Purgatives may be employed to this end, and if the case is urgent and without spasms immediate action may be sought by a hypodermic injection of 1½ gr. eserine and 2 grs. of pilocarpin. Meanwhile the horse may receive a dose of aloes or the cow one of Epsom salts. Abundance of watery or demulcent liquids given by the mouth, or as enemas, should not be omitted.

When plethora has been a prominent factor and symptoms are urgent, a free bleeding (4 to 5 quarts for horse or cow) from the jugular vein may serve to relieve the vascular tension, dilute the vital fluid, and moderate the inflammation. Hot fomentations or sinapisms to the limbs, and even cupping on the neck and chest, may contribute to relieve the tension on the spine. When the temperature is already high, bags of ice may be applied to the tender parts of the spine or those indicated to be the inflamed parts by the groups of rigid or paretic muscles. Wet compresses or evaporating lotions may be substituted. In the absence of mustard, tartar emetic, biniodide of mercury, or euphorbium may be used, or even croton oil in a carefully guarded manner, but cantharides, oil of turpentine, and other agents calculated to irritate the kidneys are to be avoided.

Bromides, hydrobromic acid, potassium iodide, chloral, or belladonna may be availed of. Some prefer ergot, but this, like strychnia, is of doubtful effect or positively injurious in most cases in the early stages. Even in the early stages electricity may be used in the form of a constant current, which tends to vaso-motor contraction and a better tone of the capillaries. The electrodes may be applied along the affected side of the spine so that the current may traverse the affected part. It may be kept up for ten to twenty minutes at a time and repeated daily. Any undue suffering under the current may be accepted as a demand for the reduction of its force or its suspension for the time being.

When the hyperthermia has subsided and the occurrence of paresis or paralysis demands nervous stimuli, these may be sought in counter-irritants, strychnia, and interrupted currents of electricity. The blisters already mentioned may be used. Strychnia may be used internally (horse or ox 2 grs., sheep ¼ gr., dog ¹⁄₅₀ to ¹⁄₁₆ gr.) or hypodermically (horse 1½ gr., sheep ⅛ gr., dog ¹⁄₁₀₀ to ¹⁄₃₀ gr.). Should this excite the animal or aggravate the symptoms it must be stopped and deferred until the inflammation shall have more completely subsided. The same remark applies to electricity which may be tried in the interrupted current, and graduated to the endurance of the patient or entirely abandoned for the time.

If the patient is able to support itself on its limbs, it is best kept in a sling to avoid the formation of sloughs and sores. If it cannot so support itself a very thick soft bed of litter is essential to avoid the sloughing and septic poisoning. Food must be laxative and easily digestible such as mashes, hay tea, and boiled or pulped roots. Fresh green grass may be employed when obtainable.

During convalescence a course of bitters with calcium phosphate and carefully regulated exercise are important. In tardy cases Trasbot especially recommends cauterization.

SPINAL MENINGITIS.

Complex cases. Microbian invasion. Lowered vital tone. Traumas.
Poisons, parasites, tubercle, rheumatism, neoplasms, poisonous food.
Symptoms: Stiffness, tonic contraction, spasms, hyperæsthesia with
warmth, enuresis, paralysis later. Treatment: parallel to myelitis;
cold, anodynes, nerve sedatives, and antispasmodics, saline
purgatives, diuretics. Iodine, electricity, cauterization.

It is often difficult to distinguish between spinal myelitis and meningitis in the lower animals, and the danger of confusion is greater because the two affections are often conjoined. Attacks appear to be often associated with microbian invasion of the membranes, but in its turn this is often favored by the lowered tone of the membranes through mechanical injury, circulatory disorder, trophic changes, or the action of poisons in the blood. Thus the condition may supervene on fractures, partial dislocations or sprains of the neck, back or loins, abscesses pressing on the spine, extension of septic inflammation from poll evil, fistulous withers, or arthritis of the vertebræ, penetration of the membranes by sharp pointed bodies (Reindl found a darning needle in a cow’s spinal canal), invasion by microbes in influenza, brust-seuche, dourine, rabies, milk sickness, distemper, pyæmia, septicæmia, strangles, louping ill, or Texas fever. The toxins of tetanus may start similar trouble. The larva of cysticercus cellulosa may cause meningitis in dogs or pigs, the sclerostoma in the soliped, the filaria in dogs and strongle in a variety of animals. Tubercle of the meninges is not unknown, and rheumatism is alleged as a cause. Neoplasms commencing in the cord act in a similar way, and the poisons of rye grass, millet, loco, lupins, tares and vetches may act on the membranes as well as on the myel.

_Symptoms._ In the main these resemble those of myelitis and are often present at the same time, and it is only necessary to note those which are especially pathognomonic. The early rigors are followed by stiffness of the back shown in rising or walking and aggravated by motion. There may be tonic contraction of the dorsal and lumbar muscles amounting at times to oposthotonos. The muscles of the limbs, chest or abdomen or some part of them may be the seat of tonic or clonic spasm. The skin is usually hypersensitive and this is aggravated by heat. The urine is liable to be retained because of the pain of stretching to micturate. Paralysis usually follows and implies extension to the myel, compression of the cord by reason of exudation, or implication of the spinal nerves at the points of exit. In myelitis on the other hand the spasms may be entirely absent, and paralysis sets in early and extends rapidly according to the seat and extent of the lesion.

_Treatment._ This will be along the same lines as in myelitis, being aimed at elimination of toxic matters, and the counteracting of the existing inflammation. Anodynes such as bromides and chloral and cold water or ice are especially called for to alleviate pain and hyperæsthesia, and antispasmodics like ether, chloroform, chloral, belladonna, etc., to allay the spasm. Saline purgatives too, and diuretics may be availed of to limit effusion and favor reabsorption. In the advanced stages iodine may be freely applied to the spine, and an occasional electric current, or cauterization may be availed of.

ACUTE MYELITIS IN THE DOG. MENINGO-MYELITIS.

Causes: distemper, in long-haired pets, pyæmia, exposure to cold,
violent overexertion, traumas, vertebral caries or abscess. Lesions:
in lumbar enlargement, horns yellowish, red, friable, pultaceous,
leucocytes in excess, punctiform extravasations, neurons opaque;
granular, filaments diffluent, varicose, sclerosis. Meninges
congested, thickened. Symptoms: as in horse, extreme hyperæsthesia,
later anæsthesia, tremors or twitching, later paraplegia. Treatment:
Laxatives, ice bags, sedatives, later derivatives, cauterization.
During convalescence, phosphates, iron, zinc, strychnia. Attend to
bladder and rectum, light, laxative diet, pure air and water.

_Causes._ This disease is a common result of distemper and according to Trasbot, is much more frequent in long-haired and pet dogs than in the short-haired and mongrels. The shelter of the hair, like the warm indoor atmosphere, seems to contribute to a special sensitiveness of the cutaneous and nervous tissues. The infective inflammation of the myel is also seen in pyæmia, rabies and milk sickness. It appears to be further induced by exposure to cold draughts when heated, or excited, by plunging into ice cold water, by lying on cold, damp, stone pavement or metallic plates. Violent overexertion, excessive fatigue, and a variety of traumatisms are further factors. Kicks, blows on the back, concussion from falling from a window or other height, and sprains received in fighting or otherwise, are common causes. Disease of the vertebræ or abscesses in their vicinity will sometimes extend to the meninges and cord.

_Lesions._ These are like those in the larger animals, being to a large extent determined by the cause and nature of the lesion, concussion, sprain, fracture, pyæmic, septicæmic, or other infection. The implication of the myel to the exclusion of the meninges is very frequent and the lumbar enlargement is the most common seat of disease. Localization in the brachial enlargement or in one lateral half of the cord is uncommon. The gray matter towards the extremity of the horn is the most commonly involved, reflecting a yellowish, grayish red or deep red color, and breaking down into a pultaceous mass on the slightest pressure. At an advanced stage the altered coloring matter gives to the tissue a brownish yellow color without altering its consistency. The still vital and vascular area around the centre of softening may be slightly swollen and abnormally firm. The neuroglia is the seat of leucocytosis, and minute (usually punctiform) extravasations of blood. The red globules are crenated or otherwise distorted and the white are granular and opaque. The neurons are swollen, granular and opaque and the nerve fibres are more or less diffluent, moniliform and in their substance show no clear outline of white substance and axis cylinder. Interruptions by granule masses and vacuoles are common. In old standing or chronic cases the liquid exudate and granular debris have been largely absorbed and the thickening of the neuroglia by fibrous neoplasm, has restored the firmness or even approximated the part to a condition of sclerosis.

In case the meninges are involved there is thickening by exudation into their substance or on their surface, there may be adhesion between the outer and inner layers of the arachnoid and a serous fluid, red, milky or clear, distends the arachnoid or subarachnoid space. The false membranes, here as elsewhere, are usually red if recent, and increase in pallor with age.

_Symptoms._ These are in the main the same as in the larger animals. The early excitement usually takes the form of hyperæsthesia. When lifted, pressed, touched or only approached the dog may growl, howl, snap, cringe, cower or tremble, glancing up meanwhile with anxious or pleading eyes. When later, this gives place to anæsthesia no such interference will draw a response. The motor disorders at the outset are mostly of the nature of tremors or twitching of the muscles of the limbs or of those parts of the trunk corresponding to the seat of the lesion. In exceptional cases spasms or convulsions may be shown. Trasbot records a case of very acute myelitis of the brachial enlargement in which there were clonic contractions of the muscles of the neck, jaws and eyeballs, and grinding of the teeth, which condition lasted for thirty-six hours. When this motor excitement merges into paralysis it usually attacks the hind limbs which are extended backward helpless while the animal pulls himself forward by his fore limbs. Some such cases are restless and in continual movement while others are dull, apathetic and indisposed to move. The precise seat of the paresis or paralysis will be determined by the seat of the lesion as in the larger animals. Thus paraplegia is most common, less frequently hemiplegia, palsy of the fore limb, palsy of a single limb, and monoplegias, about in the order named. Palsy of the tail and sphincters implies a lesion of the lumbar section of the cord and is very offensive in the incontinence of urine and fæces especially in long-haired subjects.

_Treatment._ The abstraction of blood is rarely called for in myelitis in the dog. If admissible at all it is in the case of strong, vigorous, plethoric animals which have been attacked in connection with sudden exposure to cold or accidental concussion, and which are presented for treatment at once. Then leeches may be applied to the abdomen or inside of the thigh, or the jugular may be opened with a lancet. Usually on the other hand the patient is fat, lymphatic, and, if a few days have elapsed, even anæmic, while if he has been the victim of an accident the shock and prostration would forbid any depressive measures.

Derivation toward the bowels may be sought by purgative doses of calomel or jalap. In case of high fever, cold may be applied (in the form of icebags, evaporating lotions or wet cloths) to the tender portion of the spine. If the attack has followed exposure to cold, salicylate of soda may be given, otherwise the bromide of potassium or camphor. Acetanilid and other antithermic agents may be used with caution.

With the abatement of the high fever and the supervention of paresis, if not before, counter-irritants are demanded.

Owing to the propensity to lick and the danger of absorption, poisonous agents are virtually proscribed. Yet Möller advises cantharides, croton oil, mercuric iodide, and oil of mustard, and Trasbot restricts the choice to tartar emetic one part to sixteen parts of lard. This the latter rubs softly along the spine for several minutes. If the dog is closely watched or muzzled this or the mustard or croton oil may be admissible. If otherwise, a long-haired dog may be rubbed on the spine with a combination in equal parts of strong aqua ammonia and olive oil; or it may have applied for some minutes wet cloths rather hotter than the hands can bear; or a light cauterization may be made with a Paquelin cautery. At this stage, too, bitters and phosphate of lime may be given. Trasbot has long used with the best results 1 grain doses of neutral, gelatinoid phosphate of lime, repeated two or three times a day. Iron may also be resorted to, or sulphate of zinc. Strychnia and electricity are also of great value as soon as the irritability of the spinal centres will allow of their safe employment. Massage and gentle exercise are important.

From the first, attention must be given to obviate the retention of urine and fæces, and the strict antisepsis or asepsis of the catheter adopted to prevent infective cystitis and nephritis.

Throughout the disease abundant nourishment of an easily digestible quality is demanded. Cleanliness, pure air and general comfort must not be forgotten.

CHRONIC MYELITIS. SCLEROSIS.

Sequel to acute. Result of sprains and spinal injuries. Symptoms:
paresis on exertion, lameness in one or more limbs, knuckling,
circumductive movement of feet, uncertain planting, dropping, worse if
blinded, phenomena progressive. Lesions: sclerosis of cord; absorption
of nerve cells and fibres, in gray horns, and columns, superior,
lateral and inferior, cord, altered in color, unduly firm, in points
softening. Stains deeply in carmine, lightly in osmic acid or
hæmatoxylin. Meninges thickened, nerve roots atrophied. Diagnosis:
previous acute myelitis; later muscular weakness, and paresis, under
exercise; from embolism. Treatment: hopeless if advanced: progress
delayed only. Good hygiene, tonics, open air, gentle exercise, pure
water, grooming, succulent pasture, nourishing food, alkalines, common
salt, phosphates.

Cases of this kind have not been satisfactorily diagnosed, and as a rule domestic animals affected with partial paralysis are rarely allowed to live in a condition in which they are offensive to themselves and owners, a source of constant expense with little or no hope of recovery nor profit. Again, in the case of the large mammals, the prolonged recumbency and the low grade of nutrition in the semi-paralyzed parts, usually entail unhealthy sores and septic poisoning which sooner or later prove fatal. It is only, therefore, in the slighter cases, in which a fair measure of control over the limbs remains, that these cases are likely to survive. Trasbot suggests that many cases which pass for lumbar sprains are really chronic myelitis and on careful examination will show spinal sclerosis.

_Causes._ These are largely speculative, yet doubtless the same causes which determine the acute form, will produce the chronic when acting with less force and greater persistency. The lesions that are left after an acute attack are calculated to keep up a measure of vascular and trophic disorder which will be found associated with more or less sclerosis.

_Symptoms._ In Weber’s case in the horse (Recueil de Med. Vet., 1884, p. 432) the advance was slow, so that for nearly a year the manifestations were not diagnostic. At first there was weakness of the hind limbs when worked to fatigue. Perfect rest led to improvement, and work, to aggravation which became steadily worse and worse. For a length of time the horse maintained good condition, glossy skin, elevated head, alert expression, keen sight and hearing, and normal breathing and pulse. Standing in the stall there was no abnormal position of the limbs, nor evidence of lack of perfect control.

But when moved all this was changed. He showed first lameness in the right fore limb and soon in all four members. The feet were swung and planted uncertainly, the animal swayed and staggered, the limb would knuckle over at the knee or fetlock, or bend at the hock, and be recovered with difficulty. After going slowly for a few steps he moved with greater freedom though still with difficulty, and the trouble was greatly aggravated when the eyes were blindfolded. Then every step threatened to precipitate him to the ground. The symptoms were essentially those of locomotor ataxy.

The tactile sensibility was unimpaired, the loins had the normal sensibility, urination and defecation were natural and the appetite remained good. After ten months he showed loss of condition, dullness of the special senses, stupor, and a special sensitiveness about the head, and resented its handling.

_Lesions._ Thirteen months after the commencement of the attack this horse was destroyed and the cord was found to be profoundly altered by fibroid degeneration of the neuroglia and absorption of the nerve elements (cells and fibres), the lesions affecting different portions of the gray horns, and the columns—superior, lateral and inferior. The affected portion of the cord usually shows in man a grayish, opaque or translucent appearance, with in some cases a shrunken aspect and undue firmness of texture, with at points, centres of softening. If hardened, the sclerosed sections take the carmine stain deeply, but the osmic acid or hæmatoxylin stain very slightly, contrary to what holds in health. In recent cases there is only slight thickening of the neuroglia, but when the disease is advanced the trabeculæ are thick, dense, and firm, and the nerve fibres have largely disappeared. The coats of the blood vessels adjacent to the sclerosis are thickened and their lumen is narrowed. Thickening of the meninges is not uncommon, either confined to those covering the diseased portion of the cord or extending completely around it. Atrophy of the nerve roots is often appreciable by the naked eye.

_Diagnosis._ This depends largely on the fact that the condition follows an acute attack of myelitis, on the supervention of muscular weakness and lack of muscular control, whenever the animal is exercised to fatigue, the morbid symptoms subsiding promptly when he is allowed to rest, the aggravation of these symptoms when the patient is blindfolded and a gradual though slow advance of the symptoms with the lapse of time. From arteritis and embolism it is to be distinguished by the absence of the local symptoms of pain and tenderness, and by the absence of pulsation in the same artery distal of the obstruction and of improvement by the lapse of time or a run at grass.

_Treatment_: Unless in the very early stages even a partial recovery is not to be looked for. By a run at grass or by gentle well regulated exercise the impaired nerves and muscles may be educated to a better control for a limited period but the progress of the disease is not really arrested and the final issue is likely to be ruinous. Even in man, where 90 per cent. of the cases are connected with syphilis, the fibroid hyperplasia (sclerosis) is not remedied asgummata are, by mercury and iodides. In the soliped, where no such specific disease can be charged, the repair of the structural changes is no more hopeful. The many different methods of treatment in man,—electricity, blisters, firing, stretching of the spine, stretching, of the sciatic and crural nerves,—though inducing transient improvement in many cases, produce no real permanent benefit, and are to be remanded to the region of psychic inferences which have little or no place in the therapeutics of the lower animals. Strychnia, veratrin and other spinal stimulants are of little permanent value. A general hygienic and corroborative treatment may be used with the view of retarding the progress of the disease rather than of curing it. Open air exercise, sunshine, succulent pasturage, an ample supply of pure water, and active grooming are valuable. Nourishing food is all important. Lecithin or the hypodermic injection of spermin or other rich albuminous animal product is useful. A course of bicarbonate of soda and carbonate of iron with or without bitters may be tried. When the animal must be kept on dry winter food, he should have free access to common salt and water. This favors at once absorption, assimilation, and elimination, and by fostering nutrition and the removal of waste matters, it contributes to keep the disease in abeyance. Phosphoric acid and the various phosphates have been largely used and largely rejected, their main value being in the tonic effect on the spinal centres. Trasbot especially recommends the neutral gelatinoid phosphate of lime as having proved especially valuable in his hands. He gave from 1 grain upward to dogs twice a day.

ARTERITIS (THROMBOSIS, EMBOLISM) OF THE SPINAL CORD AND MEMBRANES.

Conditions of spinal circulation favorable to embolism and microbian
invasion. Slow currents. Blood stasis. Free anastomosis a
compensation. Symptoms. Treatment.