Chapter C: F. Dawson, in investigating a wasting disease of well fed Brahma (3)

────────────┬────────┬──────┬────────┬──────┬──────┬─────────
│ │ │ │ │ │
│ │ │ │ % │ % │
│ │ │% Iliac │Lymph │Lymph │
│ │ │ and │Glands│Glands│ % Lymph
│ % │ % │Inguinal│ of │ of │Glands of
│Stomach.│Udder.│Glands. │Udder.│Flank.│Shoulder.
────────────┼────────┼──────┼────────┼──────┼──────┼─────────
German │ │ │ │ │ │
Abattoirs,│ 0.16 │ 1 │ 0.06 │ │ │
Pearson, │ │ │ │ │ │
(Penna), │ 7.2 │ 8.75 │ │ 13.5 │ 9 │ 7.75
Bryce │ │ │ │ │ │
(Canada), │ │ │ │ │ │
Reynolds │ │ │ │ │ │
(Minn. │ │ │ │ │ │
Agr. Ex. │ │ │ │ │ │
Station), │ │ 16.6 │ │ │ │
Law (N.Y. │ │ │ │ │ │
Grade │ │ │ │ │ │
Herds), │ │ 6.4 │ │ │ │
Nelson (N. │ │ │ │ │ │
J. Exp. │ │ │ │ │ │
Station │ │ │ │ │ │
Cows), │ │ │ │ │ │
Russell │ │ │ │ │ │
(Wis. Exp.│ │ │ │ │ │
Station), │ │ 6.9 │ │ │ │
Stalker & │ │ │ │ │ │
Niles (Ia.│ │ │ │ │ │
Exp. │ │ │ │ │ │
Sta.), │ │ │ │ │ │
Reick │ │ │ │ │ │
(Leipsic),│ │ 17 │ │ │ │
────────────┴────────┴──────┴────────┴──────┴──────┴─────────

────────────┬────────────┬──────┬────────┬──────┬────────┬───────
│ │ │ │ │ │
│ │ │ │ │ │
│ │ │ │ │ │
│ │ │ │ │ │
│ % │ % │ % │ % │ % │ %
│Pericardium.│Heart.│Kidneys.│Bones.│Muscles.│Larynx.
────────────┼────────────┼──────┼────────┼──────┼────────┼───────
German │ │ │ │ │ │
Abattoirs,│ 0.9 │ │ 0.7 │ │ 0.1 │ 0.13
Pearson, │ │ │ │ │ │
(Penna), │ 8.2 │ │ 2.1 │ 0.4 │ │
Bryce │ │ │ │ │ │
(Canada), │ │ │ │ │ │
Reynolds │ │ │ │ │ │
(Minn. │ │ │ │ │ │
Agr. Ex. │ │ │ │ │ │
Station), │ │ │ 2 │ │ │
Law (N.Y. │ │ │ │ │ │
Grade │ │ │ │ │ │
Herds), │ │ │ │ │ │
Nelson (N. │ │ │ │ │ │
J. Exp. │ │ │ │ │ │
Station │ │ │ │ │ │
Cows), │ │ │ │ │ │
Russell │ │ │ │ │ │
(Wis. Exp.│ │ │ │ │ │
Station), │ │ │ │ │ │
Stalker & │ │ │ │ │ │
Niles (Ia.│ │ │ │ │ │
Exp. │ │ │ │ │ │
Sta.), │ │ │ │ │ │
Reick │ │ │ │ │ │
(Leipsic),│ │ │ 52 │ 9 │ 49 │
────────────┴────────────┴──────┴────────┴──────┴────────┴───────
Footnote 2:

All serosæ.

_Swine._ The _lesions_ in swine, though essentially like those in cattle, differ in some particulars. The primary tubercles are more commonly pharyngeal or intestinal and mesenteric, in keeping with infection by ingestion; caseation will often proceed to liquefaction, so that the tubercles appear like grumous abscesses with irregular outlines and vascular growths on their walls; there is less tendency to cretefaction than in cattle; the muscular and intermuscular tissues and the lymph glands are far more frequently affected; ulceration of the pharyngeal and intestinal mucosæ is more common. The lungs, liver, spleen and visceral lymph glands are very subject to tubercle, the kidneys, uterus and testicles somewhat less so, and the nerve centres least of all. The serosæ are often involved and the seat of clusters of vascular or caseated neoplasms (grapes). The bones and joints also suffer, particularly in young growing animals.

_Horse._ The horse suffers much less frequently than cattle or swine, probably largely because of his outdoor life, his better tone as the result of muscular work, and the absence of the excessive milk secretion which is secured from cows and of the dangers from ingestion that attend on swine. Yet, according to Nocard, it is even more susceptible, and the disease once established is liable to advance more rapidly to a diffuse generalization. The _lesions_ in the lungs and abdominal cavity resemble those of cattle, both in nature and abundance; tuberculous polypi and ulcers are more common; the visceral lymph glands (bronchial and mesenteric) are early and severely attacked; the liver and spleen suffer extensively, the serosæ somewhat less so; lesions have been noted in the vertebræ, skin and muscles (Cadiot). In rare instances tubercles have been seen in the heart, and the aorta has been atheromatous (Cadiot). Necrotic degeneration, caseation and cretefaction occur as in cattle.

_Sheep and Goat._ Tuberculosis is infrequent in the goat and especially so in the sheep, owing perhaps largely to open air life and their predilection for high, airy pastures. When inoculated they show a marked susceptibility, and under favorable conditions they contract the infection casually. The tubercles may be found in all parts of the body,—lungs, thoracic lymph glands, intestines, mesenteric and sublumbar glands liver, spleen, serosæ, lymph glands at large, vertebræ, etc. There is less tendency to calcification than in the ox, the older tubercles remaining in the caseated condition or bursting and forming vomicæ. A common seat of casual tubercle in sheep is around the throat or on the sides of the cranium or face.

More frequently than in cattle, verminous affections (œsophagostoma columbiana, and venulosum in the bowels, stongylus filaria and rufescens in the lungs, linguatula denticula in the mesenteric glands) are mistaken for tuberculosis, hence the necessity for a careful investigation into the nature of the neoplasm, the presence of the tubercle bacillus, and the absence of the worms and their eggs. Except in the case of the linguatula the lymph glands are little affected by the worms.

_Dog and Cat._ The _lesions_ are often concentrated on the respiratory or alimentary tract, but they have been noted also in the pharyngeal glands, tonsils, posterior nares, serosæ, liver, pancreas, spleen, nerve centres, ovary, uterus, testicle, epididymus, tunica vaginalis, prostate, heart, aorta, bones and joints. They follow the regular development of bovine tubercle, and caseation and cretefaction are prominent features. These animals are especially liable to infection by eating the left victuals from the plate of a consumptive owner, as well as by devouring consumptive prey, and the primary lesions are to be looked for along the line of the throat, bowels, liver and lungs. For the dog Cadiot records caseating polypi and ulcers on the mucosa of the larynx, trachea and bronchia, and Müller and Cadiot several cases of pharyngeal caseating adenitis in the _dog_ bursting externally and developing intractable fistulæ, having abundance of bacilli in the discharge. These he attributes to expectorated virus from old standing tubercles in the chest infecting the pharyngeal mucosa and indirectly the lymph glands. The infection entering with the food and lodging in the follicles of the tonsils would act in the same way, and infected wounds received in fighting must also be quoted. _Cats_ suffer from similar intractable sores, some of which may be traced to a tuberculous origin. The lungs are often extensively hepatized and of a general pale grayish color, but the early miliary lesions, the caseating and cutaneous centres, the vomicæ often intercommunicating, the tuberculous bronchial and mediastinal glands and the bacilli show the true nature. Intestinal ulcers are common, especially on the agminated glands, and small tubercles, in all stages of degeneration are met with in the enlarged liver, the spleen, pancreas, kidney, etc.

_Apes and Menagerie Animals._ In these tuberculosis is common alike in the thoracic and abdominal forms, and the lesions in the main are those of domestic cattle.

_Chickens._ The _lesions_ are common in the abdominal cavity, the intestines, liver and spleen being the most frequently attacked, while the subcutaneous connective tissue, bones and joints also suffer. The lungs and kidneys usually escape. The intestinal mucosa shows small nodules, often caseated, or ulcers; the enlarged and friable liver is studded with tubercles from the size of a hemp seed upward, gray or translucid, homogeneous or with central necrosis, simply or in conglomerate masses, with congested or hæmorrhagic periphery; the spleen is swollen and permeated by similar deposits; fibrinous ascitis is not uncommon; the abdominal lymph glands are enlarged and congested.

The early tubercle shows a central, necrotic, hyaline area, consisting of the debris of disintegrated cells, which is colored brown by picro carmine, unlike the nucleus of the pheasant tubercle (Cadiot). Around the hyaline centre is a zone of large epithelioid cells, the nuclei of which stain strongly in carmine. Outside this is the usual zone of small, round, lymphoid cells. In the whole the tubercle bacilli can be made manifest by the carbol-fuchsin (Ziehl-Neelsen) stain. In the older and larger tubercles the central necrotic mass has encroached in part or in whole on the epithelio-lymphoid zone.

_Pheasant._ The _lesions_ have the same seats and naked-eye aspect as the chicken tubercle, but under the microscope the smallest and most recent tubercles show epithelioid cells to the centre, or later, the central zone presents a dense fibrous network enclosing open spaces and giving a mahogany stain with Lugol’s solution (iodine and potassium iodide). (Cadiot). There has been an organisation of connective tissue which has submitted to amyloid degeneration, making a clear distinction from the tubercle of chicken.

_Parrot._ The _lesions_ were thus located by Eberlein and Cadiot:

│ Cadiot.│Eberlein. Eye and periocular region, │ 12│ 14 Commissure of the beak, │ 7│ 11 Tongue, │ 8│ 9 Palate, │ 4│ — Larynx, │ —│ 2 ──────────────────────────────┼──────────────────────────────┼───────── Bones and Articulations, │Upper limbs (wings), 7│ 14 „ │Claws, 3│ — „ │Cervical, Dorsal and 5│ — │ Caudal, │ ──────────────────────────────┼──────────────────────────────┼───────── Lungs, │ │ 7 Liver, │ │ 4 Intestine, │ │ 3 Muscles, │ │ 1 Heart, │ │ 1

The _skin lesions_ are vascular neoplasms containing bacilli and usually invested with a covering of horn, but sometimes, on the legs and feet raw. The morbid growth may be rounded or conical, narrowing to a point. The _lesions of the buccal mucosa_ begin as small, grayish swellings on the angle of the mouth, palate, tongue or larynx which grow out into more or less rounded vegetations. The _lesions of the liver and lungs_ are mostly miliary with the usual tubercular features, but they may grow to larger size, as a pea or bean. In the _cancelli of bones_ and on their surface, the lesions resemble those of the mammal.

The cutaneous form has been held to be the counterpart of warty lupus of man, the more plausibly that the disease is developed by inoculation from tuberculous men. The arthritic type represents what is described as gout in parrots.

In any case the recent miliary lesion presents the true tubercular type of a central giant cell or cells with bacilli, surrounded by epithelioid cells, and they in turn by small, rounded lymphoid globules.

PRIMARY AND SECONDARY INFECTION.

The estimate of the relative, early or late infection of two organs or tissues may often be made with reasonable accuracy from the fact that the lesions in one organ are old, caseated, calcified or sclerosed, while those in the other organ are all recent, with vascular environment and almost devoid of caseation or other degenerative process. We cannot safely predicate our decision on the greater number of old lesions in one organ rather than another, as the disease may have advanced much more rapidly in the one tissue. Still less can we state with certainty that the disease has not entered by a given channel because no lesions are left to show the transit of the bacillus along its supposed course. We frequently find tuberculosis of the bronchial or mesenteric glands, when we can detect no lesion in the lung, nor intestine. The bacillus has been passed on without establishing any lasting lesion in transit.

It is often too confidently asserted that the infected dust inhaled, falls directly on the air cells and determines the extensive pulmonary tuberculosis that ensues. So, on the other hand, it is often too arrogantly assumed that tubercle bacilli ingested with food, must necessarily show their results mainly in the intestines, mesenteric glands and liver. That solid particles can find their way directly into the lungs, has long been demonstrated by the pulmonary anthracosis of the miner, and the deadly phthisis of the stone hewer and cutler. The experiments of Cornet, Tappeiner and others in producing pulmonary tuberculosis, by compelling the inhalation of infected spray, corroborate this experience very satisfactorily. Yet it does not follow that all of the offensive matter penetrated the air cells at once on the air inhaled. The heavy particles of steel, quartz and even of coal dust must be mainly arrested on the surface of the moist air passages, yet, under the irritation caused by their presence and the consequent arrest of the ciliary motion, they would slowly gravitate downward to the pulmonary cells. In the case of the inspired tubercular spray or dust, we must recognize the possibility of the approach of the bacillus to the lungs through the lymph and blood channels as well. The bacilli lodged in the pharynx, and, above all, in the tonsillar follicles, can readily enter the lymph vessels, and are finally poured into the lower end of the jugular vein, but a few inches from the right heart, by which they are instantly propelled into the lungs. If then the lung is the most receptive and least resistant organ, it may easily be that this is the first point where the bacillus can establish a strong and effective colony. Apart from this the colonization of the tonsillar follicles may determine a constant supply of fresh bacilli, which may gravitate down with the abundant mucus toward the lungs.

This tuberculous colonization of the tonsillar follicles is doubtless the main source of the infection of the pharyngeal lymph glands, which is so common in ox, pig and dog. It tends further to intestinal tuberculosis through the frequent swallowing of the products of the infected follicles. Then the infection of the pharynx and tonsils, whether established by inhalation or deglutition, may be the first step toward a secondary infection of the intestines.

Again the bowels can be infected by the frequent swallowing of the expectorations brought up from the diseased lungs or bronchia.

Conversely the lungs may be easily infected secondarily from preëxisting disease of the abdominal organs, and again primarily through the lymph channels. With tuberculosis of the cardia or liver the bacilli can follow the lymph vessels of the œsophagus or vena cava so as to reach the mediastinal glands, and from these glands in a state of disease they can easily pass into the adjacent pleural cavity and reach the lung. Or by following the mesenteric lymphatics they reach the thoracic duct and enjoy what is virtually for them a culture fluid, until discharged into the jugular, which, as already stated, is but a few inches from the right heart and lung.

Extension through the general blood stream usually takes place only when tubercles have already become numerous and extensive in a given region of the body, and its occurrence is the signal for a generalized tuberculosis.

The extension from the gastro-intestinal organs, pancreas and spleen may be considered as a partial exception. Here the infecting blood is not the general blood stream, but has to run the gauntlet of the liver capillaries by which the bacilli may be sifted out and delayed. This arrest subjects the liver to secondary tuberculosis in almost all cases of abdominal tuberculosis, and goes far to explain the extraordinary frequency of the disease in this organ. Ingestion tuberculosis almost necessarily leads to hepatic tuberculosis, and this notwithstanding that the primary lesion may have been very circumscribed.

The tuberculization of such a large vascular organ as the liver, however, paves the way for further extension, and if once extensively diseased, the early generalization of the infection is to be dreaded.

TUBERCULOSIS CONTINUED.

SYMPTOMS OF TUBERCULOSIS IN CATTLE.

Microscope and staining; by centrifuge; by agglutination test; by
inoculation; by tuberculin test; tuberculin; reaction; precautions,
temperature before injection, exclusive of other illness, of
parturition, abortion, heat, isolation, of hot building, of cold
draughts, of hard floor, of faulty milking, privation of water, of
change of food, of journey, of rude handling, of previous recent
tests, of antipyretics, make special examination in unthrifty, test
excluded animals later, danger of infecting through thermometer;
technique; dose; time of injecting; identification and record of
subjects; seat of injection; sterilization of syringe and skin;
temperatures hourly or every second hour from 8th to 16th or later;
typical reaction; accurate record of feeding, watering, milking or
other occasion of hyperthermia or hypothermia; passing on the value of
a rise; local swellings; chills; tremors; effect of test on general
health of reacting and nonreacting animal; action on parturient cows;
reliability of test. Relation of human to bovine bacillus; varying
character of microbes generally, of tubercle bacillus in man; bacillus
of man and bird interchangeable; tuberculosis in man and ox,
similarity, coextensive, apparent exceptions, direct infection—man to
cattle—cattle to man; encrease of tabes; experiments of Adami, Ravenel
and Garnault; experiments on cold blooded animals; bearing of
variations of susceptibility on sanitary work. Treatment: When
admissible; hygiene; rich feeding; oleaginous seeds: cod liver oil;
pneumatic cabinet; grooming; warm bath; medicated inhalations;
sulphurous acid; chlorine; formaline; calmatives; carbonate of
creosote; derivatives; streptococcic serum; air or oxygen in
peritoneum; excision of tubercle; Prevention; Extinction in cattle;
expense, supply of tuberculin and efficient veterinarians;
appraisment; indemnities; vermin; disinfection; scheduling; control of
purchases. Breeding healthy stock from infected; raising healthy
offspring without sterilizing the milk. Removal of unthrifty and
suspicious animals. Removal of animals showing objective symptoms, or,
tuberculin reaction. Generally applicable measures. Hygiene of milk,
butter, cheese, whey, oleomargarine. Hygiene of meat.

Tuberculosis may be acute or chronic, yet as seen in cattle, from casual infection, it usually comes on very slowly and insidiously and follows a chronic course. As the symptoms vary according to the organs involved it will be convenient to consider these in turn beginning with such as show the most diagnostic phenomena.

_Pulmonary Tuberculosis._ Though one of the most common and dangerous forms of the disease this may last for months or years without any suspicion on the part of the owner or caretaker of anything amiss. There may be an occasional cough, short, weak, dry, wheezing, perhaps repeated and roused by opening the stable door in cold weather, by leaving the stable for the cold outer air, by rising suddenly in the stall, by being driven on a run for a short distance, by drinking cold water or by eating dusty food. If driven for some distance, or put to draught work (ox) the subject blows more than the others. Sometimes even at rest, breathing is slightly accelerated. Yet the spirits may be as good, the eye as clear and full, the coat as smooth and sleek and the skin as soft and mellow as in health. Some such animals give as much milk, of as rich a quality, or, when put up to fatten, lay on flesh apparently as well as their healthy fellows. In favorable cases percussion may elicit circumscribed areas of dulness, and wincing or other sign of tenderness, and auscultation may detect crepitation or wheezing over the same points. By covering the nose and mouth with a sac or blanket the breathing is rendered more labored and the morbid sounds become clearer and more definite. The use of a stethoscope or phonendoscope may also render them more distinct. The morbid râles are more significant of tuberculosis if found in a number of isolated and circumscribed spots, with healthy respiratory murmur between, than if simply surrounding a single extended area of flatness as is usual in pneumonia. Much, however, stands in the way of success at this early stage. The heavy muscular and bony mass of the shoulder covers the anterior lobe and partially muffles the auscultation sound, while it renders percussion useless. The thick covering of the ribs in fat animals proves a serious barrier to successful auscultation and percussion. The varying plenitude of the abdominal viscera, and the rumbling, trickling, gurgling, and in the case of the rumen the crepitation of the contents, tend to complicate, obscure or cover up the pulmonary sounds. There is usually no appreciable elevation of temperature, or a slight rise of about one degree takes place at distant and uncertain intervals so as to render it useless for purposes of diagnosis.

When the disease is more advanced and the pulmonary lesions more extensive, the animals usually appear less thrifty on the same feeding, yet fat animals are habitually killed for food that show quite extensive pulmonary tuberculosis. With loss of condition, the coat loses its lustre somewhat, the hair becomes dry and stares in patches, and the skin loses its mobility and mellowness. The cough may be more frequent, perhaps paroxysmal under excitement, harsher, more short and broken, and either dry and husky or moist and gurgling, with a succeeding deep inspiration perhaps a moist râle. When the skin on the last ribs is pinched up between the fingers and thumb it is slower in flattening down to its normal smoothness, pinching of the spine at the shoulder or back, or it may be of the sternum, may cause wincing and even moaning, and the same may come of percussing the ribs smartly with the closed fist. There is now more decided evidence of flatness on percussion on the various affected points, and of abolition or lessening of the respiratory murmur, which is replaced by wheezing, or by bronchial blowing sound, heart beats and abdominal crepitation or gurgling, conveyed to the ear more clearly through the intervening consolidated tissue. The breathing may be slightly accelerated even at rest, and becomes distinctly so on exertion. The appetite fails somewhat and the secretion of milk lessens, or it may become more pale and watery. Chronic tympany occurring after meals occasionally appears, usually indicating tuberculosis of the glands along the œsophagus with pressure on that organ impairing eructation, and on the vagus nerve so as to impair nervous control. In connection with this there come on signs of generalization of the tubercle, as irregularity of the bowels, or enlargement or nodular induration of some of the superficial lymph glands, as the pharyngeal, prescapular, prepectoral, axillary, prefemoral, inguinal or mammary. Expectoration is usually abundant but it is difficult to secure it for diagnostic purposes since the moment it reaches the pharynx it is instantly swallowed, while any that may have been projected into the anterior nares is licked out by the pointed tongue. Nocard tried to secure this through a cannula passed in between the tracheal rings but with very little success. Others have introduced the hand into the pharynx, rousing the cough by tickling the larynx, and attempting to bring out the expectoration in the hand. When it can be secured its solid and opaque flocculi may be stained and examined for the bacillus, or it may be inoculated on a Guinea pig, intraperitoneally, to test its virulence. If there are open vomicæ or complex infection the breath is usually heavy and mawkish.

In the most advanced stages the symptoms are very characteristic. The subject is miserably thin and wastes visibly from day to day, the hair is dry and erect, most marked along the spine, the skin is scurfy, rigid, lousy, and clings firmly to the bones, the eyes are pale, deeply sunken in their sockets and bleary, the tears running over the cheeks, while a yellowish, granular, fœtid, and often gritty discharge flows from the nose, and dries in masses around the alæ. The cough is weak, painful, paroxysmal, and easily roused by pinching the back or breast or percussing the ribs. The breathing is liable to be hurried, even panting, and the animal may stand most of its time with nose extended to obviate the oppression that comes of recumbency. All the visible mucosæ are pale and blanched, and the pulse weak and rapid with every indication of anæmia. The temperature is usually raised to 104° or 105° F. and the milk secretion is completely arrested. Indications of generalized tuberculosis become more marked in the enlarged glands, diarrhœa, and clouded (purulent), or blood stained urine with microscopic casts, and even anasarca. The morbid sounds in the lungs have become a complex variety according to the nature of the lesion, blowing, wheezing, amphoric, friction, creaking, mucous, with the other bruits conveyed from adjacent organs. Death usually occurs in a state of complete marasmus, after months or years of illness.

_Tuberculosis of the Abdomen._ This usually affects the intestines, mesenteric glands, peritoneum, liver, spleen and pancreas, and has been known as _tabes mesenterica_. The generative organs also occasionally suffer, in which case, an early and rather persistent symptom is sterility, with a too frequent or it may be persistent desire for the bull (nymphomania). There is usually a steady loss of condition in spite of good feeding, the impaired functions of the intestinal mucosa, but especially of the mesenteric glands, liver and pancreas, interfering seriously with absorption and assimilation. The victims are therefore known as piners. While there may be more or less fever, highest in the evening, this is by no means marked, and cough and respiratory trouble may be entirely absent. Indications are not lacking, however, of digestive trouble. Slight tympany may follow meals, and the bowels are irregular, costiveness alternating with diarrhœa. If heavy feeding is resorted to, diarrhœa is the usual result, accompanied, it may be, by colic and tympany. There is a tendency to formation of pea or nut-like nodes under the skin of the flank, and Kleinpaul claims that the tubercles or vegetations on the rumen can be felt by manipulation of the left flank. Clearer evidence can often be had by rectal exploration, the tubercles and enlarged glands being felt on the rumen, in the knotted mesentery and in the sublumbar and subsacral region.

In case of _uterine tuberculosis_, the nymphomania may be supplemented by a purulent discharge, and rectal exploration may detect the tubercles on its surface, in the broad ligaments or even in the enlarged ovaries.

Great fœtor of the fæces may indicate ulceration of the mucosa, indigestion or impaired hepatic function.

For a great length of time the disease may be virtually confined to the mesenteric or portal glands, or even to the spleen, while the animal enjoys fairly good health. Again, in some instances, the subject may be fat and sleek, though the rumen, omentum or mesentery is to a large extent literally covered with tuberculous vegetations. The tuberculization of the intestines, mesenteric glands, liver or pancreas interferes far more with the general health than does even extensive peritoneal tuberculosis.

As the case advances it tends to generalization and winds up with the general symptoms predicated above of pulmonary tuberculosis.

_Genital Tuberculosis_ in the bull is associated with nodular swelling of the testicle, epididymus or cord, hydrocele, and exceptionally tubercle on the penis, or in the prostatic sac.

_Mammary Tuberculosis._ This may be primary and circumscribed under direct infection through a trauma or by the milk ducts, but more commonly it is secondary to generalized tuberculosis. It may be a rather firm, uniform, painless swelling of one or two quarters (usually hind ones) without at first serious interference with milk secretion. As the disease advances, the follicles and ducts being invaded, an irregular knotted condition is developed, the milk becomes pale, watery, semi-coagulated and filled with bacilli, and the climax is reached in a densely indurated condition of the gland. From the first the mammary lymph glands, behind and it may be in front of the organ, become swollen, and they are finally indurated as caseation or calcification ensues. The superficial inguinal glands often participate.

_Pharyngeal Tuberculosis._ In this rather common localisation the retro-pharyngeal glands and those on the side of the pharynx especially suffer, though the parotidean lymphatic gland and the submaxillary often participate. Enlargement and induration of the tonsils and ulceration of the mucosa may be present. There is distinct swelling of the throat or displacement downward of the larynx, and the enlarged or hard nodular, perhaps even shrunken, glands may often be detected by manipulation. The nose is carried slightly protruded and a stertor or wheeze accompanies the breathing. A glairy liquid may run from the mouth or nose, and in this, bacilli may often be detected under the microscope. The retro-pharyngeal glands are very subject to softening and liquefaction, and in such a case an obscurely fluctuating swelling may be detected above the pharynx when the hand is introduced through the mouth.

This usually terminates in generalized tuberculosis, though it will often remain for a length of time the one appreciable localization.

_Cutaneous Tuberculosis._ The counterpart of _tuberculosis verrucosa_ of man, this probably usually occurs by direct inoculation in a sore, yet the infection may reach the seat of lesion through the blood. It is usually represented by an irregular clustering warty growth, hanging more or less loosely from the skin and showing at points caseating centres. Bacilli may be recognized under the microscope.

_Glandular Tuberculosis._ Aside from the tuberculosis of the internal lymph glands already referred to, tubercles may form in any group of lymph glands, causing swelling, induration, fibroid degeneration or tuberculous abscess. Among these may be named the glands in front of the stifle or shoulder, at the root of the ear, beneath the zigoma, in the jugular furrow, the prepectoral, axillary, inguinal, etc.

_Tuberculosis of the Brain and Meninges._ Disorder of the cerebral functions occurring in generalized tuberculosis may be held to point to this disease. The earlier meningeal symptoms are often those of excitability, timidity, spasms, visual troubles, etc., merging later into vertigo, hebetude, paresis, unsteady gait, local paralysis and coma.

_Tuberculosis of the Eye._ This has been seen mostly as the result of experimental inoculation, with conjunctival and sclerotic congestion, corneal opacity, and the development of yellowish centres in the iris and choroid, from which the tubercle extends into the chambers.

_Tuberculosis of the Heart, Pericardium or Pleura._ Tuberculosis of the pleura is usually a concomitant of pulmonary phthisis, yet it may exist for a time independently, and its diagnosis presents serious difficulties. There may be tenderness of the intercostal spaces, a friction sound in case of raw granular surface or vegetations, creaking from false membranes or even flatness low down on percussion. If these escape notice, a short painful cough and slightly hurried breathing under exertion, in the absence of objective symptoms of lung disease, may lead to suspicion, but the true nature of the affection must remain in suspense. It usually leads to pulmonary or glandular (bronchial), and finally generalized tuberculosis.

_Pericardial or Cardiac Tuberculosis_ is usually secondary and may be suspected when friction is synchronous with the heart sounds, when the heart beats or sounds are irregular or intermittent, or when the area of cardiac dulness is greatly encreased.

_Tuberculosis of Bones and Joints._ This is more common in calves and growing cattle, but may be present at any age. As affecting the vertebræ it causes stiffness and unsteady gait, perhaps what was looked on as a simple sprain causes persistent lameness in spite of treatment, and a point or area of tenderness on pinching is manifest. In the large bones and joints of the limbs, the cancellated extremities, or it may be a simple process with its inserted tendon or ligament, shows a firm, persistent swelling, and there is acute synovitis of the joint. In acute cases in calves the epiphysis may become detached from the diaphysis so as to make the limb useless. In the mature animal the enlargement and lameness may last for years without material change. The condition may be difficult to diagnose, in the absence of signs of tuberculosis elsewhere in the body, or unless the synovia, withdrawn through a sterilized nozzle, with antiseptic precautions, should show the presence of bacilli.

SYMPTOMS OF TUBERCULOSIS IN SWINE.

In young pigs, infected by the milk of the dam, there are general unthriftiness, stunted growth, emaciation and unhealthy skin, encrusted with a dark unctuous matter or scurf, as in chronic hog cholera. Temperature is variable on successive days, or times of the same day. Digestive disorder is manifested by slight colics, diarrhœa, vomiting, tympany and abdominal tenderness. The pig becomes pot bellied, with hollowness of the flanks in front of the iliac bones, and manipulation may detect the tuberculous bowels and mesentery in the form of a knotted mass.

Roloff describes a caseous colitis with ulceration of the mucosa, which is probably tuberculous.

Enlargement of the superficial lymph glands (pharyngeal, inguinal, prescapular) may be present. Traumatic infection of the castration sore and inguinal glands has been noted. As the disease becomes generalized, implicating the lungs, there is a dry paroxysmal cough and hurried breathing, becoming more oppressed on the slightest exertion. If quiet and thin enough for auscultation and percussion the usual morbid lung sounds can be heard. Unlike cattle, pigs are very subject to muscular and intermuscular tubercles, and as there is a general tendency to caseation, these are usually to be found as saccular cavities with soft, sometimes liquid, caseated contents. The bones and joints may suffer, as in cattle. The tonsils are usually enlarged and even caseous. The outer auditory meatus and the interior of the eye have been found affected. Cases affecting the brain were manifested by nervous disorder, rearing up on the fence, turning in a circle, spasms, rolling of the eyes, paresis and paralysis, often hemiplegic. When one or other of these indications of local disease is found associated with the general disorder of the lungs or bowels, in a herd fed on raw meat scraps, milk, or the soiled food of tuberculous animals, the evidence is strongly in favor of the local tubercle corresponding to the symptoms. It is noticeable that diagnosis by microscopic examination is difficult and uncertain because of the relatively very small number of the bacilli. In the mature pig the disease may be difficult of diagnosis without tuberculin, and a _post mortem_ examination may be necessary to identify the disease in the herd.

SYMPTOMS OF TUBERCULOSIS IN THE HORSE.

Though not a common disease in the horse yet a large number of cases are on record, and accidental and experimental cases alike show that this animal is peculiarly receptive to the disease. The early symptoms depend on the location of the primary lesions, yet the general phenomena of debility, languor, early fatigue, unfitness for violent efforts, perspiration on slight exertion, irregular appetite, occasional rises of temperature and emaciation may usually be noted. The advance is usually slow, almost imperceptible, with periods of improvement and aggravation.

Some cases have appeared in the submaxillary and pharyngeal lymph glands with sore throat and were for a time mistaken for glanders (Ehrhardt, McFadyean). Others show a swelling of the appearance of cold abscess in the seat of the prepectoral glands (Johne, Röbert). One showed widely distributed lymph nodes and enlarged and indurated lymph glands (prepectoral, inguinal, etc.) with thickening of the intervening lymph vessels (Cadiot). This last suffered from bronchitis two months before. A number of cases reported by McFadyean showed special stiffness of the neck, with swelling and distortion of the vertebral joints, due to a tubercular osteitis and periostitis, and associated as necropsy showed with internal tuberculosis. Cases of this kind occurred in the practice of McConnell, Dawes, Insall, Malcolm and Hill, so that tuberculosis may well be suspected in cases of disease of the cervical vertebræ. In all of these cases post mortem examination, performed at once, or after a long delay, showed generalized internal tuberculosis.

When the chest is extensively affected, the symptoms are those of broncho-pneumonia or heaves (broken wind), there is hurried breathing with paroxysmal cough sometimes dry and wheezy, at others moist or mucous, a double lift of the flank in expiration, and a muco-purulent discharge from the nose, sometimes streaked with blood. Auscultation detects a varying force of the respiratory murmur at different points, with more or less wheezing. Blowing and other sounds conveyed to the ear through the solidified lung tissues are more rare or less marked. Percussion may show general resonance, encreased at emphysematous points, and diminished in small circumscribed areas, the seats of tubercle or consolidation. There are of course the attendant debility, inappetence, fever and steadily advancing emaciation. In some cases the enlarged tracheo-bronchial glands are seen to bulge forward between the two first ribs, and by the sides of the trachea. Stocking of the limbs is frequent.

Abdominal tuberculosis is most common in the young foal and when not secondary, may be due to feeding on tuberculous milk, especially in those brought up by hand on cow’s milk. There is debility, emaciation, anæmia, irregular appetite, digestive disorder, constipation alternating with diarrhœa, colics, pot-belly, falling in beneath the lumbar transverse processes, dry, harsh, scurfy skin and advancing marasmus. Rectal exploration will usually detect the enlarged sublumbar and mesenteric glands, and the simultaneous manifestations of disease of the lungs, superficial lymph glands, throat, or bones serve to identify the disease.

In the advanced stages of tuberculosis in solipeds polyuria is a frequent phenomenon (Nocard) tending to hasten the general anæmia and marasmus.

The patient often works for months or years but with gradually encreasing debility, which is soon fatal after the occurrence of generalized tuberculosis.

In estimating the nature of the disease, indications may often be drawn from the environment, feeding, etc. Nocard as the result of a careful study of the morphology and habits of the bacilli has shown that the more purely abdominal form of equine tuberculosis is near akin to that of the chicken, while the pronouncedly pulmonary form resembles the human type. McFadyean on his part adduces a number of cases of tuberculosis in horses that had been fed largely on cows’ milk, a most significant fact considering that such a ration is rare for this animal, and that few horses contract tuberculosis casually. Exposure therefore to the sputa of man, of the nasal or bowel products of birds or to the milk of cows, may suggest the probability of tuberculosis in a horse with chronic anæmia, debility and wasting.

The discharges from the nose of the affected horse are more available than those of cattle for examination and experimental inoculation, yet in many occult cases the diagnosis by tuberculin is the only reliable resort.

SYMPTOMS OF TUBERCULOSIS IN SHEEP AND GOATS.

The tubercles have been usually found post mortem in these animals or as the result of experimental inoculation, and symptoms have not been well recorded. They follow the same order as in the ox, weak husky cough, wheezing and other râles in the lungs, disorders of the digestive organs, swollen lymph nodes and glands, and caseated products in those that were of some standing. I have found these latter especially, in the region of the throat in high bred rams kept in confined buildings or yards and highly fed to prepare for _letting_ or sale. These lose in vigor and activity and _scrofulous_ swellings form on the neck, head or elsewhere and become rapidly caseated. In German abattoirs tuberculous sheep proved 0.1 to 0.15 per cent. In Saxon goats the percentage was 0.6.

SYMPTOMS OF TUBERCULOSIS IN DOGS AND CATS.

These follow in the main those of consumptive cattle. As the infection generally enters with food, the early symptoms often point to disease of the throat and alimentary tract, while the later ones involve those of the respiratory organs as well. Impaired and capricious appetite, debility, early exhaustion under exertion, emaciation, sunken pallid eyes, apathetic expression of the face, lack of life and gaiety, a knotted feeling of the abdomen if the region is flaccid, and a tense fluctuating sensation if ascitic, with usually enlargement of the superficial lymph glands are noticeable.

When the chest becomes affected there is the hurried breathing, quickly encreased by exertion, panting, paroxysmal cough, wheezing, and the various morbid râles in the chest, crepitant, friction, creaking, blowing, cavernous, mucous, etc. On percussion, flatness is detected in limited areas in a number of centres. Expectoration is usually promptly swallowed and can only be secured with difficulty for examination.

When tuberculous sores and fistulæ occur in the region of the throat or elsewhere, the evidence is patent and the bacilli can easily be found in the discharges.

In _cats_ the course and symptoms do not materially differ. In both animals the history usually shows the connection of house life and the habit of eating after tuberculous persons.

SYMPTOMS OF TUBERCULOSIS IN BIRDS.

In the gallinaceæ there may be inappetence, vomiting, diarrhœa, with hurried breathing, sneezing, and the general phenomena of debility, weakness, advancing emaciation and anæmia, the comb and wattles becoming pale and flaccid and the visible mucosæ bloodless. The eyes are sunken and lack lustre, the head sinks, the wings and tail droop, and weight is steadily lost. When the bones and joints of the legs and wings are involved the local swellings and distortions are visible indications of the trouble.

In _parrots_ these local swellings and particularly the horn-covered vegetations on the face and around the beak are characteristic.

_Canary._ Tuberculosis is common in the canary, contracted, as in the parrot, from man, with whom alone the caged bird comes into dangerous contact. The interchange of the disease between pet birds and their owners would demand the exclusion of such from the rooms of consumptives, and a careful watch for indications of disease of the air passages with marasmus, that the bird may be disposed of before it has become a source of danger.

DIAGNOSIS OF TUBERCULOSIS.

It is needless to repeat the various symptoms of tuberculosis according to its different seats and the degree of its extension in the animal body. In cases in which the indications are slight, greater importance may be given to them through the knowledge of the existence of more advanced or decided cases in the same herd, or the necropsies of animals taken from it. Yet in the average herd it is safely within bounds to say that three fourths of the affected cattle will escape condemnation if we employ objective symptoms alone. In one herd of seventy head, in which the tuberculin test condemned twenty-four head (being 50 per cent. of the mature animals), I left the examination after slaughter to the veterinarian of the A. J. C. C. who was at the time skeptical as to the value of the tuberculin test. He wrote me afterward of his surprise at finding every one of the twenty-four condemned animals tuberculous, when not one of them had shown symptoms by which he could recognize the disease in life. This is no exceptional case, and may be advanced rather as a typical example of the ordinary infected country herd.

_Microscopic_ detection of the bacillus in the expectoration may be successful in the horse with pharyngeal or pulmonary tuberculosis, but fails in those forms that affect the other internal organs. It is all but useless for the expectoration of cattle and dogs. When there is cutaneous tuberculosis or a tuberculous fistula this is much more valuable, and it is especially useful in dogs and parrots.

The precipitate in the centrifuge will often show the bacilli that are present in milk, but in very many cases of tuberculosis the bacilli are not present in the milk.

The centrifuge used on the _urine_ may also succeed when kidneys, bladder or prostate are affected, but the bacilli are rarely found in the absence of disease of these organs. The smegma bacillus is a source of fallacy.

The serous effusions in the affected _serosæ_ (pleura, peritoneum, pericardium, synovial cavities) may also be centrifuged and the presence of the bacilli revealed.

The _agglutination test_ of Arloing and Courmont though often giving positive results, (95.5 per cent. in pulmonary tuberculosis, 50 per cent. in surgical, Arloing and Courmont; 40 per cent., Knopf; 25 to 50 per cent., Lartigan); yet proved too unreliable, and frequently gave positive results when tuberculosis was absent. The best medium for cultures to be so used is 6 per cent. glycerine bouillon, and the age of the tuberculosis culture 8 to 12 days. One part of fresh blood serum of the suspected animal in a sterilized capillary tube is added to ten parts of the bacillus culture, and the tube placed in an oblique position. In 2 to 24 hours a fine sand-like material precipitates along the sides of the tube, and the microscope shows the bacilli in clumps, absolutely still without even Brownian movements. Gallemaerts found that it proved very satisfactory with the serum of Guinea pigs after three days from intraperitoneal inoculation, was less marked after inoculations subcutem, and that in man the agglutination appeared in influenza and pneumonia in the entire absence of tuberculosis. Such an uncertain test cannot be utilized in veterinary sanitary work.

_Experimental inoculation_ with milk, expectoration, morbid discharges, the scraping of nodules, etc., is much more searching, and will detect more cases than the microscopic examination. But it fails entirely in cases in which the milk of unquestionably tuberculous animals is free from bacilli, or in which the local nodule or discharge tested is itself free from tubercle. It is a test of the local lesion and not of the entire animal system.

In choosing a subject for inoculation, the first consideration is that it must come from a healthy stock and be itself free from tuberculosis. Next, it must be of a species actively susceptible to the habitual tuberculosis of the animal from which the inoculated matter is taken. Thus for man, ox, dog and parrot, the Guinea pig is especially appropriate, while for gallinaceæ and horses, the rabbit is to be preferred. Inoculation is usually made into the peritoneal cavity.

As a period of two or three weeks is usually necessary to allow of an extensive development of tuberculosis, the method must be too often discarded on account of the delay in obtaining results.

_Tuberculin test._ Many stock owners still entertain an ignorant and unwarranted dread of the tuberculin test. It is quite true that, when recklessly used by ignorant or careless people it may be made a root of evil, yet as employed by the intelligent and careful expert it is not only perfectly safe, but it is the only known means of ascertaining approximately the actual number affected in a given herd. In most infected herds, living under what are in other respects, good hygienic conditions, ⅔ or ¾ are not to be detected without its aid, so that in clearing a herd from tuberculosis and placing both herd and products above suspicion the test becomes essential.

_Tuberculin_ is the bouillon in which the tubercle bacillus has been grown, charged with the toxic products of its growth, but which has been raised to a boiling temperature to destroy all germ life, and from which the dead germs have been removed by passing it through a porcelain filter. When a physiological dose of this has been injected, subcutem, into the suspected animal, it has no effect on the non-tuberculous, while in the tuberculous it produces, in the course of the next 24 hours (usually from the 8th to the 16th), a steady rise of temperature by 2° F. or more, followed by a slow subsidence to the normal. This may last for from three to ten hours in different cases.

Among the precautions may be named:

1. The temperature of the animal is best taken at intervals, or at least, morning, noon and night, on the day preceding the injection to see that the animal shows no habitual rise at any time of the day. Yet in busy field work the one night temperature taken just before injecting will rarely fail to give a satisfactory normal as a standard for the animal. Any quotidian rise almost invariably reaches its climax at night.

2. _The subject must be in good general health._ If there is present in the system any concurrent disease it may undergo an aggravation within twenty-four hours and give a rise of temperature that will be mistakenly set down for tuberculosis. At the very start, therefore, it is important that the general health of the subject should be first assured by a critical professional examination. If some other disease is present the tuberculin test had best, as a rule, be delayed until that has subsided, while if tuberculosis is found the test will be superfluous.

3. _The subject must not be within three weeks of parturition, nor about to abort._ In many cases, though not in all, as preparations are made for calving, the system becomes unduly susceptible to the presence of tuberculin and that agent will cause a rise of temperature, though no tuberculosis is present. Unless this source of error is carefully guarded against the most valuable cows in the herd may be condemned unjustly.

4. _The cow must not be within three days of the period at which “heat” would naturally occur._ Under the excitement of œstrum the body temperature usually rises two or three degrees, and if tuberculin has been used this rise may be attributed to tuberculosis and a sound animal may be condemned. Nor is it always enough that the animal is supposed to be pregnant. Abortions sometimes take place unexpectedly and unknown to the owner. If, therefore, a cow under the test and which is not well advanced in pregnancy should show a rise of temperature it should be at once ascertained whether the animal is not in “heat.” If symptoms of “heat” are found she should be set aside along with any calving cows to be tested again when such a source of error is no longer present.

5. _The tested animal must not be exposed to a hot sun in a closed area._ In excess this will cause heat apoplexy, and the fever heat which ushers this in, may easily be mistaken for the indications of tuberculosis.

6. _Cattle taken from pastures must not be enclosed in a hot, stuffy stable._ While they must be tied up to allow of the temperature being taken at short intervals, coolness and ventilation should be secured in summer by a sufficient air space and the requisite ventilating openings.

7. _Exposure to cold draughts between open doors and windows, or to wet or chilly blasts out of doors should be carefully guarded against._ A chill proceeding from any source and alike in the presence or absence of tuberculin causes a rise of the internal body temperature.

8. _Heavy cows unaccustomed to stand on hard boards may have a rise of temperature in connection with resulting tenderness of the feet._ One must avoid hard floors on the day of the test or make examination of feet and allow for attendant fever.

9. _Omission of the previous milking or a change of milker and consequent retention of part of the milk_ will raise the temperature of a nervous cow, and in careless hands secure an erroneous condemnation.

10. _Privation of water at the regular time will often cause rise of temperature_ especially when on the dry feeding of winter. I have seen a general rise of two degrees and upward from the delay of watering for a single hour, while after watering the temperature went down to the normal and remained so. Water always tends to a temporary lowering of temperature but in the presence of tuberculosis it soon rises again.

11. _Change of food is liable to produce a slight indigestion and rise of temperature._ This should be avoided as far as possible, and when a herd is taken up from pasture for the test, it should have grass, ensilage or other succulent food.

12. Cattle just from a long journey by road or rail, or other cause of violent exertion are liable to have an elevated temperature from the leucomain poisoning. Such should be left at rest until the transient fever shall have subsided.

13. Violent handling of nervous cows in taking the temperature must be carefully avoided. The operator who cannot handle them gently is not fit for this work.

14. There must be evidence that the animals have not been repeatedly tested at short intervals shortly before. In a number of instances I have found a proportion of the cattle irresponsive to tuberculin, though a _post mortem_ proved the presence of tuberculosis. Unscrupulous men, wishing to sell on a guarantee, can avail of this in animals so unaffected by the test.

15. The operator must have absolute control, even of the feeding and watering of the animals on the day of testing. Otherwise the rise of temperature may be prevented by a liberal use of antipyretics and a false guarantee may be secured.

16. An unthrifty animal, having general symptoms suggesting tuberculosis, must be subjected to the most critical examination in addition to the tuberculin which in such animals often fails to cause hyperthermia. Fortunately in such animals the tubercles are usually numerous and extensive enough to be discovered through objective symptoms.

17. Animals excluded from the test by reason of some individual unfitness at the time (parturition, œstrum, abortion or any other disease) must be marked and held for the test later after such disqualification shall have passed.