Diseases of cattle, sheep, goats and swine

by G. Moussu; Jno. A. W. Dollar

COW-POX—VACCINIA.

The name cow-pox, or vaccinia, is employed to describe a special disease which in animals of the bovine species is characterised by the development of pustules at points where the skin is fine, and more particularly the mammary region.

It can be conveyed both to man and the domestic animals.

This disease has been known from time immemorial, and it would appear that first of all in the East and later in England it was a general belief that its attacks rendered human beings proof against small-pox. Medical men, it must be admitted, long regarded this belief as a popular delusion, as is proved by their continuing to practise inoculation with true small-pox material.

Jenner in 1770 was the first to declare the truth of this popular opinion, and by his wise foresight to confer on humanity one of the most beneficent discoveries ever made, although the weight of modern opinion is in favour of the identity of cow-pox and human variola. Having observed that milkmaids who happened to have small cuts or sores about the hands sometimes contracted the disease in a mild form, and that they did not afterwards suffer from small-pox, he was struck with the advantages consequent on such a discovery, and having proved the possibility of inoculating human beings artificially, he immediately formulated the principles of vaccination. A child eight years of age was vaccinated with cow-pox, and afterwards inoculated with pus from a small-pox patient. It contracted vaccinia in consequence of the first inoculation, but entirely resisted the attempt to inoculate it with small-pox. Vaccination had been discovered.

Jenner furthermore proved that cow-pox was transmissible from cow to cow and from man to man, but it seemed to him that the original disease was to be sought elsewhere, and that the pustular affection originated primarily with the horse. The horse is sometimes the subject of a pustular disease called horse-pox; this disease when inoculated in man confers immunity against small-pox, just as does cow-pox, and Jenner believed that the disease did not attack cows unless they had been accidentally inoculated through the medium of the people about the farm. Unfortunately, he named the pustular disease of the horse which he had studied “sore heels,” and for a long time all those who busied themselves with the question of vaccine confounded “sore heels” with a number of different diseases, although as early as 1802 Loy had experimentally proved that so-called “grease” (in reality horse-pox) was transmissible by inoculation to the cow, in which it produced cow-pox.

Loy’s “grease” and Jenner’s “sore heels” only represent forms of horse-pox, but for more than fifty years the origin of vaccine was sought in grease, lymphangitis, and other diseases which attack the extremities of horses’ limbs. Pételard (1845–1868) rediscovered and redescribed horse-pox and proved its transmissibility to man; Lafosse and U. Leblanc discovered it in an epizooty which broke out at Rieumes; and Bouley in 1862 furnished a synthetical description of it under the designation of horse-pox. He shows that horse-pox is always a pustular disease, but that it may sometimes appear in the form of a discrete eruption around the lips and nostrils, sometimes of an eruption limited to the pasterns or extremities of the limbs when inoculation has been effected in this region, sometimes of lymphangitis, and sometimes of a more or less confluent and generalised eruption.

Symptoms. The disease as discovered and described by Jenner was soon rediscovered and redescribed on all sides—by Sacco in Italy, Hering in Germany, etc.

The pustular eruption usually appears on the udder in the case of cows, and on the muzzle, nose, and lips in that of calves. In exceptional cases the eruption may become generalised.

The pustules are round or slightly elliptical, and are preceded by the appearance of red congested patches, followed by infiltration and thickening of the skin.

The pustule is moderately prominent, and after some days there is exudation at its centre, transforming it into a vesico-pustule. The exuded liquid collects under the thickened layer of epidermis, which it raises, and on examination it appears as a white or transparent little central patch, with a thin grey periphery surrounded by a reddish inflammatory zone. This liquid becomes thicker and the pustule is flattened at its centre, then, towards the eighth or ninth day, the pustule is ruptured, owing to tearing of the epidermic patch. The vaccine thus escapes.

In what is termed spontaneous vaccinia the udder is covered with a varying number of pustules, usually in different stages of development. Some are very small, whilst others have attained the size of sixpence and are already in course of cicatrisation.

When cow-pox is accidental or the result of inoculation, the eruption occurs exactly at the point of inoculation, whether the latter has been through an abrasion, a puncture, an incision, or any other skin injury, and the eruption may assume the most varied appearances, according to the nature of the primary lesion, although the mode in which the pustules themselves form never varies. Pustules experimentally produced by puncturing the parts may be taken as a type of inoculation. On the day following the operation nothing abnormal appears. On the third day there is a slight swelling around the point punctured, and this increases until the fifth day, when there is exudation, which converts the primary lesion into a vesico-pustule. On the sixth day the vesico-pustule becomes umbilicated at its centre, the exudation is abundant, and already vaccine might be collected.

This may be termed the period of crisis; the appearances are most characteristic. During the following days the vesicle is ruptured; the discharge continues from the ninth to the twelfth day, when the pustule diminishes in size and dries up. After the fifteenth day crusts of a brownish colour form; these separate between the twentieth and twenty-fifth days, leaving hard whitish-looking cicatrices, which permanently remain.

Moderate itching accompanies the development of the eruption, the principal functions are not disturbed, and fever only appears in the event of the eruption becoming confluent or extending over a large area. When the eruption is generalised the pustules or vesico-pustules are found mostly in the region of the elbow, the lower border of the neck, the flank and the inner surface of the limbs. They present exactly the same appearance as the pustules on the surface of the udder, but, being covered with hair, are less open to inspection.

In certain rare cases the eruption extends to the perineum and lips of the vulva. Signs of inflammation then develop on one or both sides, the tissues display œdematous infiltration and disseminated or confluent pustules. The lymphatic glands and vessels in the neighbourhood of the pustules are always swollen.

Causation. Cow-pox, or vaccinia, is a virulent disease transmissible by accidental or intentional inoculation. The discharge from the vesico-pustules and the crusts which afterwards cover them are virulent, and inoculation can be performed by simply scratching the skin. A first attack confers prolonged and sometimes perfect immunity, the operation being successful if only one pustule develops.

The disease is transmitted to healthy animals by milkers, by calves in sucking, or by the conveyance in whatsoever form of virulent material to sores or cuts.

The nature of the parasitic or microbic agent which produces the disease is still unknown. Some investigators have described intracellular parasites, others extra-cellular parasites, others, again, blood parasites, etc., but the exact cause has always eluded research.

It is, however, known that filtration of vaccine, pure or diluted, through porcelain removes the active material, which remains in the residue arrested by the filter.

Prolonged exposure to a temperature above 104° Fahr. (40° C.) greatly diminishes the activity of the vaccine. Simple desiccation has no action. Warming to 140° Fahr. (60° C.) for fifteen minutes also destroys its action completely.

These facts explain why it has always been so difficult to preserve and cultivate vaccine in tropical regions.

Mixed with equal parts of neutral glycerine, the virulent material preserves its activity unimpaired for from six to eight months.

The disease develops equally in man, the horse, the ox, the buffalo, the goat, and the camel. Its development is less typical in the pig, sheep, dog, and rabbit. Young animals are best adapted for its cultivation.

The blood and serum of animals suffering from cow-pox possess immunising properties, but only when administered in very large doses, say from 6 to 12 lbs. of blood, or ½ to 1 lb. of serum.

The curative action of this serum against small-pox is comparatively trifling.

The diagnosis of cow-pox is not very difficult.

At first the disease might be mistaken for false cow-pox, the eruptions of foot-and-mouth disease, or gangrenous coryza.

In false cow-pox, the nature of which is also little understood, although it is known to be contagious and is regarded by some as true vaccinia, the pustules are smaller and thinner, while the vesicle is more developed, and the disease runs a more rapid course.

In foot-and-mouth disease the eruptions are of the nature of vesicles or bullæ, not pustules. The eruption occurs in twenty-four hours or less, and can only be mistaken for vaccinia during the period of desiccation and the formation of crusts.

Finally, as regards gangrenous coryza, the hardened pustules do not produce vesicles.

The prognosis is generally favourable. The disease runs its course within relatively fixed periods, according to the development of the pustules, and recovery occurs without complications.

Treatment. No curative treatment can be laid down, the development of the disease being perfectly regular and tending to recovery. Simple hygienic precautions and cleanliness are sufficient to avoid complications due to suppuration.

COW-POX AND HUMAN VARIOLA—PREPARATION OF VACCINE.

Time and experience having proved that inoculation with cow-pox or vaccinia protected human beings against small-pox, the question arose as to the connection between the two diseases, whether or not they were identical and whether vaccinia in the bovine animal might not merely represent an alternative form of small-pox. The importance of the question will at once be understood by bearing in mind the danger to which human beings would be exposed by vaccination with small-pox virus unmodified by passage through the calf.

Nevertheless, at the present time the opinion of the early writers appears to prevail, and the theory of identity is accepted by the great majority of scientific men. The reason why experimenters in the second group came to believe in duality is that the method of inoculation chosen (by puncture) was not entirely reliable. The inoculations proved too slight, and it is only after inoculation by scarification or incision that typical eruptions can be reproduced in series.

Preparation of vaccine. Whether cow-pox and small-pox are or are not identical, the benefits resulting from vaccination are none the less real, and it is to be hoped that vaccination and revaccination will soon be made obligatory in all countries. We should then no longer have to deplore those epidemics of small-pox which periodically cause consternation in large cities and colonies.

The preparation of vaccine has been the subject of such minute care in every country that neglect of vaccination is astonishing. The material is obtained from calves or cows. In France the vaccine is prepared from animals of five to eight months old, free from disease. The old system of inoculation by puncture has been completely abandoned, the yield being insufficient, scarifications or incisions being now employed.

The animal is secured or, better still, laid down on a suitable table, and is shaven over a sufficient surface. The inoculations are made on the sides of the chest, over the thorax or elsewhere, but preferably over the flank and thorax, as being most readily accessible. The region of operation is rendered aseptic as far as possible, and scarified in lines about 1 to 2 inches in length, the lines of one horizontal row alternating with those in the next. It is imperative that the slight bleeding which may result should entirely cease before inoculation is attempted.

The scratches are inoculated with the purest vaccine obtainable, preferably with glycerinated pulp which has been kept for six weeks or two months. From the third day the lines of inoculation become prominent, and an indurated longitudinal swelling, with all the characteristics of a pustule, soon projects above the neighbouring portions of skin. On the fifth day exudation commences, and from the sixth to the seventh day a large quantity of vaccine lymph may be collected. The line of inoculation appears slightly umbilicated and surrounded by a greyish-white zone and a hard peripheral swelling.

Vaccine may be collected from the fifth day in summer to the eighth day in winter.

The inoculated area having been cleansed with boiled water and carefully dried, the little crusts covering the inoculation wounds are loosened and the wounds themselves gently scraped with a special curette of small size. The exuded liquid is very active.

The base of each swelling is then grasped in a little special clamp, which acts like a pressure forceps and causes the discharge of a further large quantity of active vaccine lymph. All the material thus obtained is mixed; an equal quantity of neutral glycerine is added, the whole is finely triturated, passed through a cloth, and stored in little sterilised glass tubes, which are hermetically sealed.

The vaccine thus prepared retains its activity for from five to eight months, if kept from the action of heat and light. Accidental germs which may have developed in the wounds and thus gained entrance to the vaccine gradually lose their activity. After from forty to sixty days the vaccine may be regarded as absolutely pure and incapable of producing accidental suppuration, as sometimes occurs when fresh vaccine is employed.

The old electuaries, dried vaccines, vaccine pastes, etc., have been almost entirely given up, the above method always yielding a pure and active vaccine. Vaccination with calf lymph should always be preferred to vaccination from arm to arm, in view of possible transmission of grave disease, such as syphilis.

TETANUS.

Tetanus is a disease characterised by tonic contraction of the muscles of one or more limbs or of all the muscles of the body.

Causation. It is due to the growth of Nicolaïer’s bacillus in some part of the body (in accidental wounds, in the uterine cavity after parturition, etc.), and the contraction of muscles is due to toxins (elaborated by the microbe), which have a selective affinity for the nervous centres.

These toxins, secreted by bacilli localised in wounds, are absorbed and carried away by the lymphatic and vascular channels and distributed throughout the body. They seem chiefly to affect the cells of the central nervous system. Infection is due to microbes capable of living as saprophytes outside the animal body.

Nicolaïer’s bacillus assumes the form of a straight rod, one end of which is swollen by the presence of a spore. It is anerobic, grows in a number of different media, most rapidly at a temperature of 100° to 102° Fahr. (38° to 39° C.), and stains well by Gram’s method.

Though quite common in the horse, tetanus is rare in other domestic animals.

In the ox it may result either from mechanical injuries, suppurating sores, or surgical operations. In the cow, goat, and sheep it sometimes assumes the form of a true enzooty after parturition if the byres, etc., are not disinfected. In male animals it principally follows castration by one of the cutting methods, and in lambs is seen after amputation of the tail. A large number of animals belonging to one flock may be affected, and Moussu has known two-thirds of a given number of castrated lambs to die of tetanus.

Despite the sensitiveness of domesticated animals to tetanic infection they may all be protected, either by injections of cultures, or by gradually increasing injections of specific toxin. The latter, however, are more efficacious when modified by the addition of terchloride of iodine or of iodine water. The blood of immunised subjects rapidly acquires antitoxic powers, which may be greatly increased for the purpose of obtaining anti-tetanic serum.

The symptoms of tetanus are the same in all species.

In the first stage the animal appears stiff, walks in a jerky way and holds the head high, with the ears pricked. The eyes are slightly withdrawn into the orbits, and the animal shows marked general excitability.

In the second stage there are muscular contractions, together with trismus, stiffness of the neck, limbs and vertebral column, spasm of the spinal muscles and muscles of the limbs (tonic contraction), and the animal has a peculiar, staring look.

In the third stage mastication becomes difficult or impossible, respiration is impeded, and the animal suffers from spontaneous attacks of muscular contraction or from attacks due to external stimulation (noises, sudden movements, changes from darkness to light, etc.).

In the fourth stage the animal is liable to fall, asphyxia threatens, and death occurs from respiratory syncope.

Recovery is quite exceptional in the sheep, goat, and ox; death usually occurs between the second and sixth days.

Diagnosis. Tetanus being less common in the ox, sheep, and goat than in the horse, the diagnosis is not so easy in these animals, but as it develops under different conditions, and as it usually attacks several animals in one byre or fold, the diagnosis is rarely very difficult. At the worst some hesitation may be felt at first, the condition being mistaken for disease of the brain.

The prognosis is extremely grave.

The treatment is, above all, of a preventive nature, investigation having proved that injections of anti-tetanic serum, before the first appearance of tetanus, are invariably effectual.

If, therefore, one case of tetanus appears in a byre at calving time or in a flock at the season when the lambs are castrated, no hesitation should be felt in preventively inoculating all the castrated animals and the cows which have calved. The quantities required are, for a cow 10 cc. (about 3 fluid drachms) and for a sheep 5 cc. of anti-tetanic serum.

This treatment, however, should be supplemented by general hygienic precautions and internal treatment, such as irrigation and disinfection of the parts affected.

Curative treatment has little chance of success. Experiments have also proved that when the first symptoms of tetanus appear, anti-tetanic serum is powerless to prevent the development of the disease. Nevertheless, as its gravity is in direct ratio to the quantity of toxin absorbed, and as the degree of this absorption depends on the length of time that the place remains infected, the first thing to be done is to disinfect and, in certain cases, curette the wounds which are believed to be the source of mischief. Although antiseptics have little action on Nicolaïer’s bacillus, they may be used. Solutions of iodine appear most active, both as regards ordinary wounds and infection of the uterus.

General tonics, diuretics, and lukewarm gruels can be given. Unfortunately the patients are often unable to swallow them. In such cases both liquids and medicines may be directly introduced into the rumen by puncturing the parts with a trocar and canula, the latter being left in position.

Intravenous injections of large quantities of normal salt solution are also of considerable value, 4 to 6 quarts per day for an ox and 20 to 40 fluid ounces per day for a sheep.

ACTINOMYCOSIS.

Actinomycosis is a disease produced by a fungus belonging to the group of oomycetes (Actinomyces bovis) which develops in the depths of living tissues in man and the ox, producing grave and sometimes incurable lesions, most commonly in and about the jaws.

Actinomycosis is very common in America, and is also met with in all parts of Europe.

Symptoms. The disease assumes many different clinical forms, but it more frequently attacks some parts of the body than others, and by far the greater number of cases occur in the ox.

ACTINOMYCOSIS OF THE MAXILLA.

Actinomycosis of the maxilla attacks young animals, and its usual seat is in the molar region, although occasionally it affects the incisors.

Fig. 268.—Actinomycosis of the jaw.

The earliest symptoms consist in swelling of the bone, which may be overlooked if within the mouth, but the outline of the jaw soon becomes deformed, generally in the middle region of the row of molars. Somewhat tender and firm to the touch at first, the tumour gradually increases in size, invades the deeper regions of the skin, and displays fluctuation at one or two points, followed by abscess formation. The pus discharged may be white, creamy, and inoffensive, but the cavity of the abscess shows no tendency to cicatrise, and the opening through which the pus has escaped is transformed into a fistula. From this moment the pus discharge is of a greyish, sanious nature, and contains a greater or less number of little yellowish grains. It soon acquires an offensive odour, and the fistulous opening is surrounded by exuberant granulations, forming a fungoid mass.

The neighbouring tissues become hardened and lose their sensitiveness, the jaw becomes completely deformed, and a condition is set up which the old writers considered as true cancer of the jaw or maxillary osteosarcoma (Fig. 268).

A probe passed into the fistula penetrates deeply, usually into the thickness of the jaw itself, and however carefully manipulated injures the diseased tissues and causes free bleeding.

If neglected, these lesions become steadily worse, mastication is more difficult, being possible only on the healthy side, and the animals lose condition and eventually die of exhaustion. The external lesion, represented by the fungoid mass, increases in size, assumes a blackish colour, and discharges an offensive liquid. Portions of it undergo mortification and give off a characteristic and extremely fœtid odour. The molars become loose and in some cases fall out, but development is usually slow, and some weeks or months elapse before this stage is reached.

When the disease attacks the region of the incisors the symptoms are much sooner apparent, and treatment is much easier. The parasitic invasion results from an injury to the jaw caused by shedding of the milk teeth. Swelling of the body of the jaw thrusts the lower lip downwards, interferes with the prehension of food, and calls for prompt treatment. The disease is rarely allowed to attain the degree of development shown in Figs. 269 and 270.

As in the preceding instance, the animals die of exhaustion unless relieved.

Fig. 269.—Actinomycosis in the region of the incisors.

Fig. 270.—Actinomycosis in the region of the incisors.

For reasons difficult to explain, but probably because inoculation is less easy, actinomycosis is much rarer in the upper than in the lower jaw. The disease develops exactly as above described, but shows much less tendency to external ulceration. It invades the maxillary sinus and the region of the palate, and fistulæ are found opening into the buccal cavity, while at the same time the region of the forehead is often deformed.

ACTINOMYCOSIS OF THE TONGUE.

Actinomycosis attacks the tongue apart from any lesion of the jaws, and produces what is commonly called “wooden tongue.”

The disease develops in the tongue itself, generally in the submucous zone, and causes chronic interstitial inflammation, infiltration of the connective tissue, and, in time, changes in the muscular structures themselves.

The tongue shows progressive hypertrophy, and becomes hard, sensitive, rigid, and incapable of free movement. As a result the patients first have difficulty in grasping food, then in swallowing their saliva, which dribbles from the mouth, and finally are quite unable to feed themselves.

Fig. 271.—Actinomycosis of the tongue.

The tongue is enlarged and indurated, and fills the entire cavity of the mouth. Sometimes it projects beyond the incisors, excoriated and bleeding. On passing the hand into the mouth it is found that the surface is covered with little yellowish or red ulcerated nodules, varying in size from that of a large pin’s head to that of a lentil.

In eating, the animals seize food between the lips and lift the head high, so as to allow the food to fall between the rows of molars. The motion is very similar to that of a fowl drinking.

ACTINOMYCOSIS OF THE PHARYNX, PAROTID GLANDS AND NECK.

Actinomycosis may sometimes leave the mouth and tongue unaffected and attack the pharynx, from which it extends in the direction of the parotid glands and external surface of the neck. In these cases, however, the inoculations are more localised than when the surface of the tongue is attacked, and the lesions consist of vegetations, polypi, or actinomycomata.

The growths develop on the posterior pillars of the fauces, on the sides of the pharynx, or near the entrance to the œsophagus. They interfere with swallowing, and produce symptoms which are easy to detect and interpret.

The lesions may also affect deeper seated tissues and produce growths in the parotid or subparotid region, or lead to the development of fistulæ in the region of the neck. Most fistulæ, however, in this region are due to specific inoculation of external injuries. Fistulæ originating in the parotid region and in the upper part of the neck usually resemble in appearance the maxillary fistulæ. The external fungoid growth, however, is less exuberant, suppuration is less abundant, and the surrounding induration less extensive.

Various localisations. Although the disease generally attacks the mouth, tongue or pharynx, it may invade the œsophagus, rumen, reticulum, liver and intestine, larynx, trachea, lung, peritoneum, epiploon, and even the udder.

Fig. 272.—Actinomycosis of mammary gland (cow).

Localisations in the udder and peritoneum are commonest in pigs, and it is believed that inoculation occurs either through the galactophorous sinuses or through the abdominal wounds made for purposes of castration.

Causation. The cause of actinomycosis is to be sought in the development of Actinomyces bovis within living tissues. It seems problematical whether the germs to be found in the pus or saliva of affected animals ever directly infect new hosts, and it is difficult to carry out infection in this manner even in very sensitive experimental animals. Nevertheless, the persistence of the disease in certain byres would seem to support the view of direct infection.

On the other hand, it is proved that the actinomyces is a parasite affecting vegetables, principally the graminaceæ, and that domestic animals are most commonly infected through injuries caused by vegetable substances. This is suggested by the discovery of the débris of grain at the point where the lesions have originated.

Fig. 273.—Actinomycosis of mammary gland (cow), showing growth invading lobules. (Figs. 272 and 273 are from blocks kindly supplied by Mr. Gilruth, F.R.C.V.S.).

Inoculation is commonest in the mouth and on the surface of the tongue, parts which are, so to speak, permanently excoriated. The shedding of the temporary molars favours such accidents, and this is why actinomycosis of the jaw is, relatively, so common. The incisor region may also be inoculated during the shedding of the milk teeth, but as the infected food comes more closely and for much longer periods in contact with the molars, it is easy to understand why actinomycosis is rarer in the incisor region.

The conditions are less favourable for inoculation of the pharynx, because food does not remain in position there for more than a second or two, but when the epithelium has been shed as a consequence of laryngitis or pharyngitis, infection may occur.

As regards cutaneous inoculation, the parasite only seems dangerous when the skin is excoriated or injured either accidentally or as the result of surgical interference.

Fig. 274.—Old-standing bone lesions in a case of actinomycosis of the jaw.

Actinomycosis of the lung is probably caused by the germs being inhaled along with the inspired air.

Lesions. The lesions are very peculiar in character, and end in completely destroying the tissues invaded.

Once lodged within an organ, the disease shows a tendency to extend in all directions, and, despite the defensive reaction of the tissues, it soon forms numerous parasitic centres.

In bones, for example, actinomycosis invades the spongy tissue with the greatest ease. It causes subacute ostitis, which leads to diffuse suppuration and local hypertrophy of the bone, destruction of the compact layers, and the development of an abscess with fungoid, exuberant, granulating walls which show no reparative tendency whatever.

The pus of the abscess and the liquid from the fistula contain varying quantities of yellowish grains, representing clusters of actinomyces. The surrounding tissues, muscles, tendons, skin, etc., are all involved before long in the inflammatory process, and the granulating masses themselves are invaded by the yellowish parasitic tufts. All the fistulæ are surrounded by enormous zones of infiltration, which on incision exhibit a lardaceous appearance. On section it may appear that the lesion is confined entirely to the bone, though this is exceptional (Fig. 274). Ordinarily the neighbouring tissues are also destroyed, and not infrequently there is communication with the external air. Sections then display a fungoid tissue, interspersed with perforated lamellæ of bone and lardaceous tissue containing cavities crammed with actinomyces.

Fig. 275.—Highly-magnified clump of actinomyces.

The lesions in the parotid regions, the neck or other parts attacked always present the same appearance, viz., wide, tortuous, bifurcated fistulæ, with exuberant granulations both in the direction of the cavities and of the exterior, together with lardaceous induration of the tissues and abundant fœtid liquid pus.

When it affects the tongue the parasite is to be found in the submucous region, where it causes little swellings, which, when superficial, rapidly undergo ulceration. The subjacent regions, the interstitial connective tissue, and the muscular tissue become infiltrated, hardened and progressively sclerosed. The tongue is gradually hypertrophied, and soon it becomes as hard as wood, whence the term “wooden tongue.”

Actinomycosis of the lung may easily be mistaken for tuberculosis, for the centres, although usually confined to one lobe, may also be disseminated. The lesions, however, are surrounded by an abundant fibro-sclerous inflammatory tissue.

In the abdominal cavity, particularly in sows, actinomycotic lesions occur as little masses varying in size between that of a pea and that of a haricot bean, attached to the epiploon and peritoneum and filled with pus containing mycosic grains.

Diagnosis. Actinomycosis is usually easy to recognise, both on account of the special character of the lesions and the presence of the little grains formed by the parasite. The practitioner will rarely fail to recognise at once the signs of actinomycosis of the jaw, but actinomycosis of the tongue is more apt to be mistaken for deep-seated sclerosing glossitis, although a careful examination will always enable the different symptoms to be distinguished.

It is otherwise with regard to growths in the pharynx and œsophagus, for, until after removal, simple polypi cannot be distinguished from actinomycotic growths. In such cases the administration of iodide of potassium affords valuable indications.

The prognosis is grave, whatever the clinical form of the disease. Important advances, it is true, have lately been made, and the iodide of potassium treatment is of great value, but too much must not be expected of it, and its benefits have certainly been exaggerated. Clinical experience suffices to prove that only actinomycosis of soft tissues can be cured by drugs, bony lesions being amenable only to medical and surgical treatment combined. Even combined treatment is often unsuccessful.

Treatment. Thomassen in 1885 first explained the favourable action of iodide of potassium on actinomycotic growths, and Nocard in 1892 again directed public attention to the advantages attending the use of this drug both in man and the lower animals. As too frequently happens, however, the benefits of this treatment have been exaggerated, and iodide of potassium has been held out as a specific even against lesions in bone. With very few exceptions this is incorrect, and, as Moussu has shown, when the disease affects bone tissue it only yields to mixed treatment.

The treatment of actinomycosis may therefore be considered under two heads.

Firstly, the treatment of actinomycosis of soft tissues; and, secondly, that of bone.

Actinomycosis of soft tissues, muscle, skin, lymphatics, serous membranes, etc., comprises the most common forms of actinomycosis, viz., those of the tongue, pharynx, parotid glands, neck, etc.

The second form comprises actinomycosis of the lower jaw (molar region), the upper jaw, region of the incisors, etc.

Iodide of potassium in daily doses of from 2 to 3 drachms is almost a specific in dealing with the first form of disease.

In lingual actinomycosis, for example, the effects may be seen a few days after treatment is begun. The tongue becomes softer and more mobile, can be protruded beyond the mouth and retracted into it, and day by day tends progressively to resume its normal appearance.

The patients, which were previously slowly dying of inanition because they were unable to feed themselves, again take to their food and begin to put on flesh. To ensure the treatment being efficacious it should, as a rule, be continued for three or four weeks.

During the course of this treatment the system becomes saturated with the drug, but no bad effects follow. The patients suffer from lachrymation, coryza, bronchorrhæa, and especially iodic eczema, but all these symptoms diminish and disappear soon after the administration of the drug is discontinued.

Recovery, however, is not always permanent, and even when the tongue has resumed its normal appearance a relapse may occur. We have seen several such cases after treatment extending over more than six weeks, and it is therefore often advisable to fatten the animals as rapidly as possible and prepare them for slaughter.

If no relapse occurs, and recovery is regarded as permanent, another complication may make its appearance, viz., sclerous atrophy of the tongue. This is almost as dangerous as the primary lesion, because it prevents the animals from feeding, and constitutes an additional reason for following the course above suggested.

Other lesions of soft tissues, such as disease of the parotid or cervical glands, etc., yield to the same treatment, but it is advisable first of all to clean out the fistulæ, scrape off exuberant granulations, cleanse the irregular culs-de-sac, and thoroughly curette all accessible parts.

Treatment is much longer than in the case of actinomycosis of the tongue, but it is not always necessary to push the remedy to extreme limits. As soon as symptoms of iodism appear only a drachm or two of the drug need be given daily.

Actinomycosis of Bone.—As a general rule, actinomycosis of bone resists the administration of iodide of potassium, a fact probably explained by the much less abundant blood supply in bone as compared with very vascular tissues, such as the tongue.

To have any chance of success the iodide treatment must be supplemented by surgical interference. As regards the surgical aspect of the case, the affected bone should be removed as far as possible, together with all broken down tissue. Should this be neglected, the disease returns in a little while.

In actinomycosis of the region of the incisors the method is radical when adopted in time. The body of the maxilla can be partially removed with a fine saw, two cuts being made disposed thus: < (the letter V sideways). The upper and lower layers of compact tissue should be spared as much as possible, so that the body of the bone may not afterwards break. Recovery is only a matter of time.

A very small local iodoform dressing is applied, and, when healthy granulations appear, cicatrisation can be left to natural means.

Cases of actinomycosis of the jaw are much more troublesome. If, as usually happens, the lesion is ulcerated before the practitioner is called in, the external fungoid growth should be removed by means of an elliptical incision through the skin, the axis of the ellipse being parallel with the branch of the maxilla. The bony fistula is then exposed.

In following up this fistula care must be taken not to injure the facial artery, the facial vein, or Stenon’s duct. Once the bone is exposed the disease can be attacked in the depths. The diseased interior is cut away by means of a special curette, all affected portions being removed, and an iodine or iodoform dressing is then applied.

The operation is extremely troublesome, owing to the enormous bleeding, and sometimes it is impossible to carry out successfully, as in the case of old-standing and extensive lesions. To ensure recovery under such circumstances, it is necessary to remove a portion of the branch of the jaw, and this, though quite possible from the scientific standpoint, would not be worth while in an animal, the value of which is usually small.

Curettage of the bone is only of value in dealing with recent lesions, and even then should not be practised except in the case of animals which the owners particularly desire to keep.

In cases of actinomycosis of the upper jaw surgical treatment is just as difficult as in the lower jaw, and calls for similar precautions.

The diseased portions of bone having been removed, the cavity is plugged with iodoform or cotton wool, or a dressing saturated with boric acid and iodoform.

In all surgical operations it is important not to injure the dental arteries or nerves, or the alveolo-dental periosteum.