months.
=Treatment.= The patients should be isolated, and any brushes, combs,
etc., with which they have been in contact must be disinfected.
The diseased areas should then be dressed with some fatty substance, to
soften the crusts and enable them to be removed without injury.
Dressings are useless unless these crusts have been removed, for the
spores are always in the deepest recesses and in the follicles, so that
the drugs employed never come in contact with them.
Once the skin is cleansed, numerous chemical substances may be utilised,
the solutions being applied for several days in succession. Amongst them
may be mentioned tincture of iodine, oil of cade, 10 per cent. solution
of sulphate of iron, and solution of perchloride of iron. Such drugs,
however, must not be used for a long time, as they all attack the skin
to some extent.
When the patches are small and well defined the following mixture proves
very efficacious:—
Crystallised carbolic acid } Equal parts.
Tincture of iodine } „
Chloral hydrate } „
Two or three applications generally prove successful.
Despite the natural activity of the spores, which are capable of
germination after three months’ desiccation, some medicines are useful,
although it is necessary, in order to judge of their effects, to wait
for the renewal of the skin, hair follicles, and hair.
Where the disease is generalised this form of treatment is scarcely
practicable, or at least it becomes more difficult.
Nevertheless, by dressing with soft soap the disease may be cured in a
few months. The soap should remain on the skin for some hours and then
be washed off, after which dressings of creolin, lysol, or chloral
solution, etc., should be employed.
RINGWORM IN THE SHEEP, GOAT, AND PIG.
Little information regarding the dermatomycoses of the sheep, goat, and
pig is available. Allowing for modifications due to the nature of the
coat, the =symptoms= of recorded cases seem to indicate a close
relationship with ringworm in the horse and ox.
In sheep suffering from ringworm, the wool is at first matted into small
irregular tufts, which grow larger and more numerous. The coat appears
felted together at various points. The neck, chest, shoulders and back
exhibit crustaceous patches covered with branlike epidermal scales, and
the animals suffer from marked pruritus, which causes them to rub and
injure the coat.
Ringworm is very obstinate in the goat.
Two pigs described by Siedamgrotsky showed irregular, rounded patches,
due to trichophyton, from 1 inch to 2 inches in diameter, reddish in
tint, without exudation, but covered with abundant scales.
In the pig ringworm attacks the croup, sides of the chest, flanks and
sides of the abdomen, but is commonest on the back and outside of the
quarters. It forms red isolated patches, from 1 to 2 inches in diameter,
covered with miliary vesicles, which in turn are replaced by brown
crusts. The bristles remain unchanged, and are not shed or broken. There
is no pruritus. Contagion from pig to pig occurs readily. The disease
may be conveyed from oxen to pigs through the medium of litter removed
from the cowsheds to the piggery.
Gerlach was unable to inoculate sheep or pigs with ringworm from the ox.
Perroncito mentions a case of contagion from the ox to a lamb.
Schindelka has seen sheep contract ringworm as a result of confinement
to sheds previously occupied by oxen suffering from the disease.
Siedamgrotsky successfully inoculated two pigs and two sheep with
ringworm from the horse and a goat with the bovine form of the disease.
The two pigs inoculated two others by contact. Contagion from the goat
to the ox was noted in the canton of Zürich in 1852.
Fuller particulars on these heads will be found in a series of articles
by Neumann in the _Revue Vétérinaire_, January to June, 1905.
In 1876 Laillier communicated to a French medical society a letter
written by Lespiau describing an endemic of trichophyton disease in the
cantons of Céret and Arles-sur-Tech. Thirty-four persons, including
twenty-eight children, were affected. A dog was first attacked and seems
to have inoculated a pig, which in these districts often lives with the
human family. The pig inoculated the human beings. A moist season
appears to have favoured the development of the disease. The parts
principally attacked were the head, eyebrows, cheeks, and neighbourhood
of the genital organs. The subjects showed considerable pruritus.
CHAPTER IV.
WARTS IN OXEN.
Warts are cutaneous tumours, real papillomata, which most commonly
attack young animals such as heifers. As a rule they are pedunculated,
smooth, wrinkled or deeply cracked on the surface, but in some cases
they are sessile.
=Causation.= The cause is difficult to ascertain. It has been referred
to the growth of bacteria (_Bacterium porri_) in the superficial layers
of the skin. It is at least certain that warts can be transmitted by
inoculation or through the medium of cutaneous injuries.
=Symptoms.= On their first appearance warts consist in hypertrophy of
the cutaneous papillæ, which become covered with layers of actively
growing epidermis and end by projecting above the general surface. The
lesions may remain isolated, or they may become confluent or unite at
their base. This form is fairly common, the warts attaining the size of
a man’s fist or more.
The disease attacks the most tender portions of the skin, such as that
covering the udder, internal surface of the thighs, lower abdominal
wall, region of the elbow, posterior surface of the ears, etc. In rarer
cases warts may be seen on the limbs.
When they extend over a considerable surface they become infected,
suppurate and give rise to various complications, the most serious being
pyæmia. The patients lose condition and value.
=Diagnosis.= The diagnosis is easy. It has been proved that warts are
contagious, not only as between animal and animal, but as between animal
and man.
=Prognosis.= Warts are not dangerous to life, but they diminish the
value of the animals, particularly that of milch cows when the teats are
affected.
=Treatment.= Leaving out of account internal medication with calcined
magnesia, many medicines that are still recommended are of comparatively
little value.
Peuch and Cruzel recommend friction with oil of cade. Repeated
cauterisation with nitric acid is declared to give good results by
destroying the new tissue.
These modes of treatment, however, are impracticable in dealing with
large multiple lesions, nor does the elastic ligature give much better
results.
Total removal with the scissors or bistoury, or simply tearing out by
hand, is preferable to any other course. Troublesome bleeding may
follow, but is rarely of great importance. It usually stops in a few
minutes, even where small arteries of the size of several millimètres in
diameter have been divided. As a measure of precaution, however, the
little wounds may be touched with the red-hot blade of the
thermo-cautery.
The _écraseur_ is rarely required. The smaller warts are generally
sessile, and can be removed with a bistoury or a sharp curette. The
removal of those about the udder requires considerable precaution to
avoid injuring the teats.
[Illustration: $1]
All the growths are usually removed at one operation; Moussu has thus
taken away 30 lbs. weight without the slightest ill effect. After the
wounds have been washed with an antiseptic, the raw surfaces are
powdered with a mixture of equal parts of boric acid, tannin, and
calcined alum; cicatrisation occurs in a few days.
URTICARIA IN THE PIG.
This disease usually attacks pigs during the spring or summer, producing
characteristic cutaneous lesions, which, however, are of a benign
character. It seems to arise from some form of alimentary intoxication.
=Symptoms.= At first the dominant symptoms point to disturbance of
digestion. The appetite is lost, and the bowels may be confined or there
may be diarrhœa. This is sometimes accompanied by vomiting, and by
fever.
The symptoms may develop fully in from six to twelve hours; sometimes
the skin is covered with slightly prominent reddish patches, varying in
size from ⅓ of an inch to 1¼ inches in diameter.
The patches may also become confluent and form large, irregular red or
violet flattened swellings, sensitive to the touch and spread over the
upper and lateral portions of the body. Only in exceptional cases is
there any oozing of blood.
In favourable cases recovery takes place in forty-eight hours, and even
in grave cases in from five to six days.
=Diagnosis.= It is sometimes very difficult to distinguish this
condition from swine erysipelas, particularly in the first few cases,
although the congested or hæmorrhagic patches occupy different
positions.
=The prognosis= is usually favourable.
=Treatment.= The disease being unquestionably of digestive origin, the
animals should be kept without food and receive repeated doses of mild
purgatives according to their age and condition, sulphate of soda, 4 to
12 drachms, or calomel, 1½ to ·8 grains. Recovery is rapid.
SCLERODERMA.
This term is applied to a disease characterised by thickening and
hardening of the skin. Up to now it has been described only in the pig,
and principally in male animals or old animals of either sex.
=The symptoms= are difficult to detect, and in many cases are only
discovered after slaughter. Without any change in external appearance,
the skin becomes thick, hard and sclerosed over limited or extensive
areas, and is thus transformed into hard, rigid, inextensible and
inelastic plates, sometimes as much as 1 to 2 inches in thickness. The
change usually commences about the dorsal region, and extends
irregularly towards the chest and sometimes towards the limbs.
The patient thus becomes imprisoned in a kind of cuirass, which
interferes with its movements and causes unaccountable stiffness.
Palpation of the skin gives the impression of a piece of wood, for it is
hard and resistant over the affected regions, whilst over the belly,
inner surface of the thighs, and region of the elbow, it retains its
usual pliability.
The patient exhibits no other symptoms, the principal functions of the
body appearing to be properly performed. There is no fever, but in time
the animals lose condition and waste away.
=Causation.= This disease is also well known in man, but no general
agreement exists regarding its nature. Some refer it to disturbance of
the thyroideal function, though scleroderma is quite different to
myxœdema. Others attribute it to changes in the cutaneous blood-vessels,
others, again, to peripheral neuritis accompanied by atrophic
disturbance. Nothing, however, is proved.
The apparent =lesions= are limited to hypertrophic sclerosis of the
dermis, with progressive atrophy of the layers of subcutaneous adipose
tissue.
=The diagnosis= is comparatively easy.
=The prognosis= is grave, because it is never known how rapidly the
disease may develop.
No method of treatment being known, the animals should at once be
slaughtered.
CHAPTER V.
SUBCUTANEOUS EMPHYSEMA.
By subcutaneous emphysema is meant the condition produced by the
entrance of air or gas into the subcutaneous and interstitial connective
tissue. Emphysema may remain localised or it may become generalised,
according to the nature and extent of the lesion which causes it, and
the points where emphysema is developed. Subcutaneous emphysema is
common in the sheep and ox.
=Symptoms.= Sometimes the symptoms of subcutaneous emphysema are
extremely well defined. They consist in the presence of diffuse or
limited crepitant swellings which may appear at various points—in the
flank or the entrance to the chest; more rarely in the region of the
elbow, etc.
The limits of crepitation may be ascertained by palpation, while
percussion produces a peculiar abnormal sound. The subcutaneous tissue
and very often the interstitial tissue appear as though blown out.
Emphysema may be generalised. Such an accident is rare, but may occur in
the ox as well as in the sheep and goat.
Provided the emphysema remains confined to the subcutaneous tissue, the
animals are not necessarily in danger. Where, however, it also extends
to the interstitial tissue, and particularly if the cause to which it is
due continues, death may result in a very short time. This occurs, for
example, when the emphysema extends into the mediastinum, and thus gains
the pleura and lung.
The symptoms of emphysema are then complicated with respiratory and
circulatory disturbance and with signs of asphyxia.
=Causation.= Subcutaneous emphysema may be produced in many different
ways.
If, for example, in puncturing the rumen the canula be carelessly
withdrawn so that the skin is slightly separated from the subjacent
tissues, gas may pass from the rumen into the channel produced by the
instrument. It then becomes distributed throughout the subcutaneous
tissue, and if the cutaneous opening is displaced its escape is confined
to the connective and interstitial tissues in the region of the flank.
Diffuse suppuration may then be set up in these parts, and may extend
far beyond them.
In the ox emphysema rarely becomes generalised, but in the sheep and
goat extension is more common; the patients perish of intoxication,
caused by reabsorption of septic gases.
Under other circumstances emphysema may be due to an injury in some
region where the connective tissue is loose and pliable, as for instance
the region of the elbow, the internal surface of the shoulder, or the
fold of the flank. Every time the animals move the tissues are
displaced, and air being drawn in, it is imprisoned by the valve-like
action of the injured part and gradually finds its way into the
subcutaneous tissue.
Accidental injuries to the trachea, particularly injuries produced by
dogs biting sheep or goats, are always accompanied by local emphysema,
unless the wounds in the skin and trachea correspond, which rarely
happens. At every respiration a portion of the air expelled passes into
the peritracheal tissue, from which it gradually invades neighbouring
parts, and may attain the mediastinum, etc. The injured animal thus
inflates its own tissues and dies from asphyxia.
The open =lesions= due to pulmonary echinococcosis, and the accidents
associated with pneumo-thorax, tuberculous caverns and abscesses, or
pulmonary emphysema may become points of departure for local, general,
interstitial or subcutaneous emphysema.
=The diagnosis= of accidental emphysema presents no difficulty, for the
local swellings can only be mistaken for those of black-quarter. In the
latter disease, however, fever is a constant accompaniment, whilst in
simple emphysema it is absent.
Nevertheless, it is well to remember the possibility of complications
due to compression, asphyxia, and even intoxication.
=The prognosis= may be very hopeful or very grave. Everything depends on
the primary lesion, and it is therefore important that the practitioner
should know how to interpret the course of affairs.
=Treatment.= In slight cases the best method is to immobilise the parts
and await developments, but in grave cases, for instance where the
trachea is much injured, the animal should at once be slaughtered.
Scarification, cutaneous incisions, and massage were formerly
recommended as a means of aiding the escape of gas accumulated in the
tissues. Such methods, however, are useless, and have the disadvantage
of causing numerous suppurating wounds.
Provided the initial wounds are not seriously infected and the animals
are kept quiet, in a well-ventilated place, the gas gradually becomes
reabsorbed, and healing may take place in a fortnight or three weeks.
SECTION IX.
DISEASES OF THE EYES.
In domesticated animals, apart from parasitic diseases, the diseases of
the eye which particularly deserve description and offer a special
clinical interest are very few. These are the diseases that affect the
globe of the eye or the organs annexed to it.
FOREIGN BODIES.
Foreign bodies become lodged on the internal surface of the eyelids, in
the folds of the conjunctiva, in the thickness of the cornea, and
sometimes, though rarely, in the anterior chamber, the lens, or the
vitreous humour. They include particles of grit or dust, the awns and
glumes of grain, etc.
The eyes are half closed and the conjunctiva is swollen, whilst the eye
weeps and the animals dread the light.
=Diagnosis.= This is somewhat difficult, for the parts rapidly become
very sensitive, and the animals violently resist examination. When the
foreign body penetrates the anterior chamber or the lens, it produces
suppuration or traumatic cataract.
Before anything can be done it is often necessary to render the parts
anæsthetic by instilling a few drops of cocaine solution into the eye.
The foreign body may then be discovered by close observation. If the
pain is very intense, and great resistance is offered to opening the
eye, the practitioner may confine himself to passing a soft camel-hair
brush saturated with cocaine solution over the surface of the eye and
into the conjunctival sacs. The brush loosens, and often removes, the
offending body. In the absence of a camel-hair brush, the little finger,
covered with a piece of fine linen, may be used.
Where the parts cannot be touched owing to the resistance of the animal,
lukewarm solutions of antiseptics such as boric acid may be occasionally
injected into the eye by means of a syringe, but care must be taken to
prevent the animal injuring itself against the syringe by sudden
movements.
CONJUNCTIVITIS AND KERATITIS.
Inflammation of the conjunctiva and inflammation of the cornea almost
always occur together, and reciprocally induce one another when of a
certain degree of intensity. They may be simple, that is to say,
produced by simple causes, or they may be specific, and of a contagious
character.
Simple inflammation is caused by the action of cold, draughts, dust, or
mechanical injuries. Specific inflammations, the nature of which is
still little understood, occur in the ox and goat. They are very
contagious, and may successively attack all the animals of a herd.
=The symptoms= of acute and specific inflammation differ very little.
They comprise congestion, lachrymation, chemosis, a certain amount of
suppuration, and sometimes superficial ulceration of the cornea. The
patients suffer very acute pain, avoid the light, present all the
symptoms of photophobia, and are affected with spasm of the orbicularis
muscle.
In simple cases these symptoms frequently disappear, provided the byres
are kept clean and astringent eye-washes are applied.
In contagious keratitis, however, the cornea may suppurate and even
become perforated after a few weeks.
=Treatment.= The chief object of treatment under any circumstances must
be to insure the most perfect cleanliness both of the globe of the eye
and the conjunctival sacs.
The eye must, therefore, be irrigated with lukewarm water, the stream
being injected beneath the lids. Each irrigation is followed by the use
of an anodyne and astringent eye-wash containing borate of soda or
sulphate of zinc, combined if necessary with cocaine.
Distilled water 100 parts.
Borate of soda 4 „
Hydrochlorate of cocaine 1 „
But saturated solution of boric acid is simple, and no less effective.
In contagious keratitis the eye lotion may contain 2 to 3 per cent. of
nitrate of silver, the excess of silver being neutralised by washing out
with a weak solution of common salt. After three or four applications
this should be changed for a saturated solution of boric acid.
VERMINOUS CONJUNCTIVITIS.
This form of conjunctivitis, described by Rodes in 1819, is due to the
presence of the _Filaria lachrymalis_, which varies in length between ⅜
of an inch and 1 inch.
Like ophthalmia, the disease attacks cattle reared in wet localities.
=Symptoms.= The symptoms are those of acute conjunctivitis, and consist
first of lachrymation, then of injection of the blood-vessels of the
conjunctiva, together with swelling of the eyelids and photophobia. The
animals keep the eye closed, and display extreme sensitiveness. Here
again cocaine proves of value.
Examination is rather difficult, the worms being sometimes displaced
towards the cornea or membrana nictitans, although more commonly they
remain hidden in the folds of the mucous membrane towards the point
where the membrana nictitans is inserted. It is, therefore, necessary to
thoroughly expose the folds of the mucous membrane in order to discover
them.
In time conjunctivitis becomes complicated with diffuse ulceration,
keratitis, and sometimes with ophthalmia and suppuration of the eye.
=Diagnosis.= The diagnosis is rather troublesome, and cocaine is of
great assistance.
=Prognosis.= This is rather grave.
=Treatment.= The object of treatment is the complete removal of the
parasites. This can sometimes be attained by means of the finger, a pair
of forceps, or a very clean feather.
Treatment is completed by injecting an antiseptic and anti-parasitic eye
lotion for several days, lest some of the worms should remain hidden in
the folds of the mucous membrane. One per cent. creolin or 1 in 2,000
sublimate solution may be used.
If in some exceptional case it is difficult to remove the parasites,
they may be got rid of by injections or free irrigation. The stream of
liquid, pointed in different directions, distends the mucous membrane
and washes away the foreign bodies on its surface.
VERMINOUS OPHTHALMIA OF THE OX.
This ophthalmia is due to the presence of a small worm, ⅔ of an inch to
1¼ inches in length, which has been regarded as the larval form of the
_Filaria cervina_ of the serous cavities.
It is very common in animals which are kept permanently in low-lying
meadows particularly in some parts of France, as for instance in
Normandy, in the departments of the Sarthe and the Mayenne. Not
infrequently it occurs as an epizootic, and is then regarded as a
contagious ophthalmia. Verminous ophthalmia occurs chiefly during the
spring and autumn.
=Symptoms.= The disease is accompanied by lachrymation, signs of
conjunctivitis, and fear of light. Very soon the media of the eye become
turbid, the sclerotic and cornea are injected, and finally exhibit
marked opalescence.
On examination the eye appears extremely sensitive; in fact, it can
scarcely be touched unless cocaine solution is previously applied.
The parasites, two or three as a rule, but in exceptional cases from
five to seven in number, are seen rolled up within the anterior chamber
of the eye. A week after the beginning of the attack, however, they
begin to move about, and are then found close behind the cornea, upon
the lens, or suspended in the aqueous humour.
The irritation produced sets up inflammation of Descemet’s membrane and
the cornea, together with iritis, and, secondly, keratitis and changes
in the lens.
Unless treatment is adopted verminous ophthalmia inevitably ends in
cataract.
=Diagnosis.= Diagnosis is always uncertain on account of the difficulty
of examination. When the cornea is very opaque examination necessarily
gives a negative result.
=The prognosis= is grave.
=Treatment.= Eye lotions containing tincture of aloes, creolin,
corrosive sublimate, etc., have been suggested, but are practically
useless, because they can have no action on a parasite enclosed within
the globe of the eye. The most logical treatment consists in aseptic
puncture of the anterior chamber of the eye towards its lower border
with a cataract needle.
The escaping liquid carries with it the parasites, and recovery is then
only a matter of time, provided the wound does not become inflamed. The
great danger consists in inflammation and suppuration of the eye. This,
however, can be avoided by antisepsis and by applying a surgical wool
dressing, which can be left in place for a few days.
SECTION X.
INFECTIOUS DISEASES.
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.
[Illustration: $1]
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.
[Illustration: $1]
[Illustration: $1]
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.
[Illustration: $1]
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.
[Illustration: $1]
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.
[Illustration: $1]
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.
[Illustration: $1]
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.
[Illustration: $1]
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.
TUBERCULOSIS.
Tuberculosis is a contagious disease produced by the action of Koch’s
bacillus. It is common to man and all domesticated animals, but it
specially affects animals of the bovine species. Its existence has long
been recognised, although in oxen it was formerly confounded with the
lesions of peripneumonia and echinococcosis.
It was not until the beginning of the nineteenth century that Laënnec
(1811) described the tuberculous lesion from the anatomical and
pathological standpoint. Gürlt pointed out for the first time in 1831
the similarity, the identity in fact, of tuberculous lesions in man and
the ox.
In 1865 Villemin showed that tuberculosis could be conveyed from animal
to animal, always producing similar lesions, and in 1868 Chauveau proved
that, in the calf, infection might arise simply from the eating of
tuberculous material.
At a somewhat later date doubts were entertained regarding the identity
of human and bovine tuberculosis. Virchow denied the identity of the two
diseases on the basis of a comparative study of the lesions. His
opinion, however, has not prevailed, and the doctrine of the identity of
tuberculosis in mammals still appears probable, in spite of the recent
declarations of Koch (1901).
=Causation.= Tuberculosis is due solely to the activity of the tubercle
bacillus. In 1884 Koch isolated and cultivated this bacillus in living
animals, and always reproduced typical tuberculous lesions by injecting
cultures. In 1887 Nocard and Roux described a rapid method of
cultivating the bacillus, and in 1890 Koch announced the discovery of
tuberculin.
The tubercle bacillus assumes the form of a little rod, five or six
micromillimètres in length, and ·03 to ·05µ in thickness. It has a
special staining reaction when treated with Ehrlich’s or Ziehl’s
solution. It grows between 98° and 104° Fahr. (37° and 40° C.) in
various artificial media containing glycerine.
Healthy subjects become infected by the accidental entrance of germs
into their bodies, either by the respiratory and digestive tracts, or
through solutions of continuity in the skin.
The material from tuberculous centres is virulent, whether consisting of
sputum or discharge, saliva, fæces, urine, milk, etc., or tuberculous
tissues derived from the different viscera.
The blood and muscular tissues are not always virulent, even in cases of
generalised tuberculosis.
The virulent organisms usually enter the body through the lymphatic
system; invasion proceeds from the point inoculated towards the nearest
lymphatic glands and thence along the chain of lymphatic vessels, and
the lesions extend, attacking the internal organs more or less rapidly.
The body does not necessarily become fatally infected as a consequence
of accidental or even experimental infection, for the bacillus may
itself be destroyed by the phagocytes, or the lesion may remain purely
local.
Although tuberculosis is the gravest and most widespread disease on the
surface of the globe, its contagious character is relatively little
marked, a fact which has unfortunately led to its receiving little
attention in ordinary life.
Contagion is usually the result of cohabitation, although contact
between diseased and healthy subjects for a period of some days or even
weeks does not seem sufficient to produce the disease. Nocard has fixed
a mean period of five to six months as necessary for the contraction of
the disease by bovine animals, and Moussu has arrived at almost
identical results by placing tuberculous and healthy cows together in a
byre reserved for such researches. In this connection, however, very
great differences of individual susceptibility exist, and these are
difficult to appreciate in the present state of our knowledge. It thus
happens that an animal of vigorous appearance and in good condition may
easily contract tuberculosis, whilst a thinner and less vigorous one
will resist it for a comparatively long time.
Speaking generally, it may be said that young animals contract
tuberculosis by cohabitation in infected places more easily than adult
or aged ones, and the fact that old animals contribute the larger number
of cases is to some extent due to their having in the course of their
lives been more exposed to continued or successive infection.
Contagion does not occur in byres unless as the result of the presence
of animals with open tuberculous lesions, such as caverns in the lungs,
tuberculous bronchitis with ulceration of the mucous membrane,
tuberculous metritis, enteritis, etc. The virulent germs are expelled in
the saliva, nasal discharge, excrement, etc., and are distributed over
the forage, manure, litter, and in the drinking water; after desiccation
they may be spread by currents of air.
The mangers, racks, drinking pails, and various stable utensils become
permanently contaminated, the air of the cowsheds contains virulent
dust, and the animals there confined are continually exposed to
infection either through the respiratory or digestive passages.
Contamination through the respiratory tract is by far the most frequent
cause of the evil, and recent experiments at Pouilly-le-Fort (1900) have
shown how easy it is to convey the disease experimentally by inhalation.
Patients suffering from closed tuberculous lesions of the pleura,
pericardium, spleen, peritoneum, etc., do not spread the bacilli.
Healthy animals may remain in contact with them without danger, but it
is well to remember that such cases are quite exceptional. As a rule the
lesions are of a mixed character, and the general principle may be laid
down that cohabitation of any duration with tuberculous subjects is
dangerous.
Contagion spreads more easily, in proportion to the number of
tuberculous subjects in a given byre, to the total number of animals in
a herd, and to the neglect of cleanliness, good feeding, ventilation,
etc.
Life in the open air and at grass greatly diminishes the chances of
contagion. The virulent products are then disseminated in all directions
and are soon destroyed by the general atmospheric conditions. Close
confinement in ill-ventilated stables, on the contrary, strongly tends
to the propagation and development of tuberculosis.
In calves infection may occur through the alimentary tract by means of
tuberculous milk, whether such milk is obtained directly from the udder
or out of a pail. The same may be true of young pigs fed with skimmed
milk.
Goats contract tuberculosis somewhat readily by confinement in byres
with tuberculous cows, and Moussu declares that contagion afterwards
spreads just as rapidly among goats as among cows. The vaunted great
resistance of goats to tuberculosis, formerly so often spoken of, and by
some wrongly considered as a condition of immunity, is deceptive, and if
tuberculosis is less frequently seen in goats, this is solely because
goats enjoy the greatest liberty at all seasons.
On the other hand, the disease is very rarely conveyed to sheep, even
when they are kept for long periods with tuberculous cows. Moussu found
that two years of close cohabitation were necessary for its development
under these conditions.
Heredity is a factor of the highest importance in determining the
causation of tuberculosis. At the present time a tendency exists to deny
this, but such a view is erroneous.
Observation has clearly shown that tuberculosis is rarely conveyed from
the mother to the fœtus, and that practically none of the calves borne
by tuberculous mothers react to tuberculin (95 per cent.: Nocard and
Bang); but even if this is absolutely correct, it only shows that great
benefits might be derived if proper sanitary organisation and
intelligent hygienic conditions in byres were found everywhere in the
country. Unfortunately in practice this is far from being the case.
These non-tuberculous calves are left in common contaminated byres,
where they rapidly become infected and perpetuate the disease.
Physiologically these facts are easily explained. The placenta resists
the passage of microbes, or at least only allows them to pass under
quite exceptional conditions, and practically only when the
blood-vessels are affected. As, on the other hand, tuberculosis of the
ovaries, Fallopian tubes or uterus generally prevents pregnancy and
causes sterility, there is nothing extraordinary in the fact that
tuberculosis is not hereditary in the strict sense of the term. The
influence of the sire has been invoked, but it has been proved that
direct paternal infection is only possible where ulcerating tuberculous
lesions of the testicle, prostate, or vesiculæ seminales exist. Such
conditions seldom or never occur in the sires of domestic animals.
As a general rule, therefore, it may be said that tuberculosis is not
hereditary. New-born animals become infected during the months following
birth, either directly through the alimentary tract when the mothers are
suffering from mammary tuberculosis, or, perhaps more frequently,
through the respiratory and digestive tracts.
But although microbic infection is not hereditary, it by no means
follows that the offspring of tuberculous subjects are as well prepared
for the struggle of life as the descendants of healthy subjects. What is
transmitted is a greater tendency to contract the disease.
This aptitude or predisposition is of such importance that in Moussu’s
opinion it should be regarded as one of the essential factors in the
development of tuberculosis. The cause of tuberculosis is Koch’s
bacillus. It does not always produce its full effects in animals born of
healthy parents; but in one that suffers from a tuberculous hereditary
taint tuberculosis appears.
Physiological and pathological researches cast considerable light on
this question. In tuberculous mothers the organism not only suffers from
the infection, but from a permanent intoxication which interferes with
normal metabolism in the vital organs and the exchanges between mother
and fœtus. If the microbes remain confined to the system of the mother,
their poisons are conveyed by the blood and pass through the placental
barrier. In a greater or less degree they saturate the tissues of the
little creature in process of development, and communicate to it a
peculiar hereditary taint. The effects of this taint are often
noticeable from the moment of birth, for comparative physiological and
pathological investigations have shown that the tissues of tuberculous
animals assimilate given foods less perfectly and are the seat of
greater losses of all kinds than those of healthy subjects.
Although the disease itself, therefore, is not hereditary, it is
otherwise with the organic taint which plays so important a part in its
development. This organic taint consists in a special condition of the
tissues or cells of the parents, which show a diminished power of
resistance to the action of the germs of tuberculosis; it is therefore
easy to understand how important a part these influences may play under
certain conditions.
Without doubt, in the case of bovine animals, the predisposition could
be neutralised in carefully managed studs by the immediate isolation of
the new-born under conditions which shield them from tuberculous
infection, and experiment has shown the benefits derived from such
precautions; but it must not be forgotten that intelligently managed
studs are the exception, and that for a long time to come we must in
practice take cognisance of the actual conditions under which the
disease develops.
=The lesions= of tuberculosis vary greatly in appearance, according to
the organs affected, though the method of development is always
identical.
The primary lesion corresponds to what has been termed tuberculous
granulation, or anatomical tubercle properly so called; this, the
macroscopical, pathological entity, assumes the form of a small
prominent centre, semi-transparent, greyish, opaque or yellowish,
according to its age.
These tubercles, produced by the presence of colonies of bacilli, are
due to the defensive reaction of the invaded tissues, which gradually
undergo change and are destroyed in a direction radiating from the
centre towards the periphery. The tubercle in itself has no very
specific character—only the bacillus.
The elementary lesion may remain isolated, but very frequently it is
closely surrounded by other similar tubercles, and becomes enveloped in
a common inflammatory area. A large portion of an organ may appear as if
riddled with tubercles of different age and size, while the interstitial
connective tissue reacts and forms fibrous separating partitions. The
general appearance is that described under the term “diffuse tuberculous
infiltration.”
At a still more advanced stage in the development of the disease
conglomerations are produced, consisting of tuberculous masses the size
of a hazel-nut, a walnut, an egg, a man’s fist, or even larger. These
lesions, irrespective of size, undergo caseous degeneration from the
centre towards the periphery.
In exceptional cases the tubercles remain fibrous. More frequently,
particularly in animals of the bovine species, they become infiltrated
with lime salts. Caseous degeneration not only invades the centre of the
tubercles but also the peripheral layers, and sometimes the whole of a
conglomerated mass.
Steadily pursuing their course of pathological development, the
tuberculous masses become softened and are transformed into tuberculous
abscesses, which open towards any free passage, leaving behind sometimes
ulcerations, sometimes caverns of varying sizes, or blind simple or
bifurcated fistulæ.
Recent experiments by Nocard and Rossignol (1900) prove conclusively
that a certain time (always more than a fortnight) elapses between the
moment of entry of the contagion into the organism and that at which its
effects become manifest by furnishing a reaction to tuberculin.
Calcification or softening of the lesions, moreover, never occurs in
less than fifty days.
According to the organs studied, these tuberculous lesions assume
certain appearances, which in each locality seem almost always to be
identical.
Thus, as regards the larynx, trachea, and bronchi, the tubercles develop
in the depths of the mucous membrane, rapidly undergoing caseous
transformation, softening and purulent degeneration, and producing
numerous isolated or confluent ulcerations in the air passages.
According to the case and the kind of animal affected, the lung presents
either disseminated tuberculous formation, tuberculous infiltration,
tuberculous conglomeration, or cavern formation.
The lung may be affected to such a degree that it appears incredible
that the blood can have been sufficiently aerated to support life.
The lungs may be transformed into yellowish, caseous, calcareous, or
softened masses enveloped in thick, fibrous, resistant walls. The
intervening pulmonary tissue may be healthy in appearance, or reddened,
congested, and sometimes hepatised.
The pleural, pericardial, and peritoneal membranes may be covered with
exuberant tuberculous lesions, like ripe mulberries, in consequence of
fusion and massing of the tuberculous growths. The primary tubercles are
surrounded with fibrous walls, which granulate when on the surface of a
serous membrane, and impart to the membrane a vegetative, sometimes
villous appearance, and a colour varying from pink to light or dark red.
The collective lesions lining the cavities are described by butchers
under the significant term of “grapes.” In the interior of these
exuberant masses, which sometimes form layers an inch or more in
thickness, the tuberculous lesions undergo the usual developmental
changes, that is to say, they become caseated or infiltrated with lime
salts, but they do not so readily undergo softening as those of the
lung. The parietal and visceral serous membranes readily become adherent
at numerous points, setting up union between the lung and the walls of
the chest, or the intestine and the walls of the abdomen, etc.
In the pericardium the vegetations are frequently of a fungoid
character.
Tuberculosis of lymphatic glands sometimes assumes a disseminated,
discrete form or that of a diffuse infiltration, or, again, in
old-standing cases it constitutes a massive tuberculous conglomeration.
In point of fact, the lymphatic glands as such no longer exist, their
tissue having undergone total degeneration; they are represented only by
an enlarged, thick, fibrous shell, forming the envelope which encloses
caseated and calcareous masses of a more or less soft nature.
Tuberculous infiltration of the submaxillary and sub-parotideal
lymphatic glands interferes with swallowing and breathing, compresses
the pharynx, œsophagus and larynx, and deforms the head.
Compression of the arteries, veins, nerves, etc., at the entrance to the
chest may cause various symptoms which are not difficult to interpret.
The glands at the entrance to the chest and the whole of the anterior
mediastinum may form a single mass. Lesions in the posterior
mediastinum, however, are of even greater importance and explain certain
symptoms, such as difficulty in swallowing, spasm of the œsophagus,
mechanical contraction of the œsophagus, permanent tympanites, etc., for
which the state of the lungs alone would not account.
Even when the lungs are unaffected it may happen that the lymphatic
glands of the mediastinum (superior or inferior œsophageal lymphatic
glands) and the bronchial lymphatic glands may be so diseased that the
œsophagus is completely surrounded and compressed by them, and its
function thus seriously impaired (Fig. 276).
In the abdomen the mesenteric glands are most exposed to disease, and
when infected through the intestinal tract they assume the form of large
flattened masses arranged along the mesentery.
In the digestive tract, as in the trachea and bronchi, tuberculosis has
a marked tendency to assume the ulcerative form. Disseminated or
aggregated tubercles develop in the thickness of the mucous membrane,
and, after rapidly softening, become ulcerated. The nature of these
lesions can only be determined by noting their character and examining
the discharge.
[Illustration: $1]
The ulcerations are localised in the mouth and pharynx, in the second
half of the small intestine towards the ileum, and in Peyer’s patches.
Tuberculous lesions develop in the vaginal sheath of the male genital
organs exactly in the same way as in an ordinary closed serous cavity;
tubercles may also develop on the surface or in the substance of the
testicle. They become aggregated, undergo softening, spread towards the
interior, and may break down, thus forming abscesses. In the female
genital passages the disease invades the thickness of the walls, but
shows a marked tendency to ulceration, as in the intestine or trachea.
In the udder tuberculosis is generally diffuse, shows a tendency to
hypertrophy and the free formation of fibrous or sclerous tissue; only
tubercles in the glandular layer of the acini become ulcerated. In time
the whole of the secreting structure undergoes diffuse tuberculous
suppuration, fibro-caseous masses form in the depths of the tissue and
may soften, producing deep-seated tuberculous “cold abscesses.” The
mammary lymphatic glands are affected in the same way as other lymphatic
glands.
In the joints tubercles appear either on the synovial membrane or in the
thickness of the bony epiphyses, very often at both points
simultaneously. The synovial membrane is covered with vegetations and
villous growths, the ends of the bones are attacked by a destructive
ostitis, tubercles or tuberculous centres form in the thickness of the
spongy tissue, the articular cartilages are destroyed, the ends of the
bones become deformed, and in the last stages fungoid arthritis in
various forms may be produced.
In bones the tubercles originate in the depths of the spongy tissue.
They produce destructive hypertrophic ostitis, in which the bony tissue
is replaced by tuberculous centres or masses divided by fibrous
partitions. On section, these lesions exhibit the same yellowish
caseated or calcified appearance as the lesions of other affected
organs. The compact layer may sometimes be perforated at several points
before being destroyed.
In tuberculosis of the brain the primary lesions develop at the expense
of the serous layers of the arachnoid and on the pia mater, towards the
base of the brain and the fissure of Sylvius, or at the expense of the
small vessels which penetrate the depths of the nerve substance itself.
Some tubercles remain isolated, become confluent or are collected in
masses of different sizes, and provoke symptoms which vary with the
locality attacked.
=Symptoms.= Tuberculosis is the most protean of all diseases, and at
first sight it often seems impossible to assign to one group, clinical
conditions presenting such essentially different appearances. All the
tissues may be attacked, from the bones to the most delicate of the
viscera, a fact which explains why all aspects of tuberculosis cannot be
described. Certain forms, however, occur very frequently, and may be
regarded as classic; these will be considered in the order of their
frequency.
TUBERCULOSIS OF THE RESPIRATORY APPARATUS.
Without doubt this form of tuberculosis is by far the most frequent. It
assumes the form either of bronchitis, laryngo-bronchitis, or pulmonary
tuberculosis.
=Tuberculous Bronchitis.=—The symptoms of tuberculous bronchitis do not
essentially differ from those of ordinary bronchitis, though the disease
develops more insidiously and slowly, and is seldom accompanied by
fever. At first the cough is dry and suppressed; later it becomes
paroxysmal, and at a still more advanced period liquid and rough. The
least irritation brings on these attacks of coughing; changes from the
warmth of the stable to the coldness of the outer air or _vice versâ_,
the presence of dust or the action of liquids when drinking, etc., etc.
During the first stage coughing is not followed by expectoration, but
later yellowish-grey, glairy mucus may be discharged: more frequently it
is coughed into the pharynx and swallowed.
These symptoms continue for weeks or months without showing any tendency
to abate. If the larynx is attacked inspiration becomes rattling and
difficult, while the neck and head are held extended, and the least
pressure over the larynx produces coughing.
Tuberculosis of the larynx, trachea, and bronchi is usually accompanied
by disease of the lung, but may occur by itself.
When there is a discharge it consists of thick, viscous, sticky mucus of
a peculiar greyish-yellow colour. Microscopical examination shows it to
contain tuberculous bacilli.
=Pulmonary Tuberculosis= usually assumes the chronic form, and is almost
always preceded by specific bronchitis. The patients retain their
appearance and condition for a longer or shorter time, and, without the
experience resulting from continued observation, it would be difficult
to believe them to be suffering from the slow development of a serious
disease.
Frequent coughing without any apparent reason is the only symptom likely
to arouse suspicion.
At a later stage these animals lose condition, feed less eagerly or
exhibit capricious appetite, and sometimes well-marked and repeated
digestive disturbance, such as slight tympanites with constipation or
diarrhœa, moderate impaction of the rumen, relative atony and slackening
of peristaltic movements. The wasting gradually becomes more marked or,
in the case of pregnant or milch cows, makes intermittent progress,
until the animals become anæmic and finally cachectic. The cough is more
frequent and more severe, and is followed by discharge from the nose or
by swallowing movements. From this time phthisis, properly so called,
exists.
The course of the disease is not invariable. Certain animals may appear
ill for years without clinically showing the least apparent aggravation;
others on the contrary, though living under similar conditions, are
rapidly attacked, and in six to twelve months exhibit all the signs of
advanced phthisis. Pregnancy, suckling, and prolonged lactation favour
the development of the disease by taxing the physical resources of the
animal.
Animals suffering from phthisis exhibit a peculiar appearance. They are
extremely thin, all their soft tissues are wasted, the limbs are dragged
in moving, respiration is rapid and sometimes jerky, the mucous
membranes are pale and discoloured, and the skin is tight and adherent
to the subjacent tissues.
These general signs, however, would not warrant a diagnosis, for, apart
from the cough, certain other diseases present all the external
appearances of the last period of tuberculosis (chronic diarrhœa,
chronic forms of poisoning—bacterial or otherwise—dyspepsia, etc.).
In cases of doubt it is essential to discover by percussion and
auscultation that the external signs are really the result of lesions of
the lung, and that the lung disease has developed gradually in
accordance with the signs shown by simple external inspection.
The symptoms presented during the development of the pulmonary lesions
may be divided into three phases.
In the =first phase= percussion gives no information, though
auscultation reveals rough respiration, inspiration and expiration being
also unequal. Expiration, which, in the healthy subject, is silent,
becomes clearly perceptible, not over the whole lung, but usually over
the anterior lobes, particularly the cardiac lobes. This sign is the
result of tuberculous infiltration and of the neighbouring pulmonary
tissue having lost its elasticity.
Inspiration is rough and rasping, and sometimes occurs in several
stages, the act being interrupted or jerky; expiration lasts longer than
inspiration, is rough and prolonged, but never blowing in character.
These peculiarities are only found in one other condition of the lung,
viz., emphysema.
The patients appear little affected in this, the first, stage of
tuberculosis. But for the cough they may seem perfectly healthy.
In the =second phase= the tuberculous infiltration extends and ends in
the massing, by fusion or centrifugal growth, of the tuberculous masses.
Percussion may now indicate localised dulness, but this is not
invariable, because the diseased anterior and middle lobes of the lung
are concealed beneath the muscles of the shoulder. When dulness is
noted, it is usually over the lower part of the posterior lobes, very
rarely at any higher point on the side of the chest. Frequently the
dulness is only partial.
On auscultation the signs met with during the first stage become much
more marked. Inspiration is always rough, rasping, painful and difficult
at certain points, particularly in the anterior zones. In this region
expiration is rough, prolonged and sometimes of a clearly marked blowing
character. This is particularly the case in the subscapular zone and the
auscultation zones 2 and 3 (Fig. 166). In the dorsal region and in zone
No. 1, respiration may appear normal. Nevertheless, the sounds are
propagated to a distance, the infiltrated lung steadily loses its
elastic qualities, the vesicular murmur entirely disappears from the
affected regions, and the sounds noted are of bronchial origin.
Like the first, the second phase may vary in intensity, extent, and in
the diffusion or localisation of the tuberculous lesions. Blowing
respiration may be noted over different areas, accompanied by sibilant,
snoring and migratory mucous _râles_. The vesicular murmur is
exaggerated in the healthy parts, coughing, accompanied by expectoration
or followed by swallowing movements, is frequent, the appetite becomes
capricious, and the general condition suffers. In this second phase
almost the whole of one lung may be diseased and exhibit the signs
described.
The =third phase= corresponds to the softening of the tuberculous
masses, and the formation of ulcers and caverns. The zones of dulness or
partial dulness may be more extensive, though cavern formation is
usually confined to the anterior or middle lobes. Percussion still
affords no precise information.
As the tuberculous masses undergo softening and ulceration, their
contents are gradually passed into the bronchi, and auscultation reveals
signs indicative of the existence of caverns, which signs vary with the
dimensions of the caverns themselves. On auscultation the respiration is
always found to have at certain points a blowing character, and it may
even develop into a true tubal souffle. In other areas, where the
caverns are merely in course of formation, gurgling sounds are all that
are heard, but where true caverns exist there is an incessant cavernous
souffle.
The lesions peculiar to the third phase are seldom seen in practice;
because the animals become anæmic, exhausted and cachectic, they are
usually slaughtered early. Nevertheless, the third stage occasionally
develops in an astonishingly short time, six to eight months at most.
Very frequently the patients, although cachectic and even phthisical, do
not yield on auscultation the sounds described as peculiar to the third
stage, because the tendency to softening is not very marked in bovine
animals. The lungs exhibit massive infiltration, and, whilst pulmonary
consumption is not uncommon, the development of caverns is comparatively
rare.
The expectoration or discharge in this third form is puriform, glairy,
viscous, and of a dirty-yellow or even greenish-yellow colour.
Bacteriological examination reveals the presence of tubercle bacilli and
adventitious organisms.
These conditions are always associated with various complications, and
the second and third stages of chronic tuberculosis are frequently
accompanied by lesions of the pleura, of the mediastinal lymphatic
glands, of the liver, etc.
Digestive disturbances often occur; the appetite is capricious or in
abeyance, there is atony of the rumen and chronic dyspeptic tympanites.
These disturbances are easily understood where there are lesions of the
liver, intestine, and mesenteric lymphatic glands, but not when the lung
alone appears the seat of the disease. In this condition the patients
probably suffer from permanent complex intoxication, due to toxins
elaborated by the tubercle bacillus and other microbes which multiply on
or in the lesions, and this chronic intoxication reacts on the vital
functions (innervation, secretion, digestion and nutrition). Nor are the
effects limited to these appearances; the heart’s action is also
accelerated, and the temperature rises. During the first and part of the
second phase there is comparatively little fever, but afterwards this is
continuous or of a peculiar intermittent character. In the morning the
patient’s temperature may be normal; in the evening it has risen from
1·5 to as much as 9° Fahr. (1·1 to 5·2° C.) above normal, and this
recurs day by day. These attacks coincide with softening of the lesions,
and when suppurating caverns exist they are more marked and more nearly
continuous, assuming the characters of the hectic fever shown in
consumption.
Often during the febrile periods the urine is albuminous.
In chronic tuberculosis of bovine animals bleeding from the lung is rare
even when caverns exist, and Moussu, in spite of extensive experience,
has seen only two cases. This is in striking contrast with the condition
in human sufferers from pulmonary tuberculosis, two-thirds of whom bleed
at the lungs.
TUBERCULOSIS OF SEROUS MEMBRANES.
After pulmonary tuberculosis, tuberculosis of the pleural and peritoneal
serous membranes is the most frequent clinical form of this disease.
Sometimes both forms exist, and although the pleural and peritoneal
lesions predominate or alone attract attention, there are also lesions
in the lung or mediastinal lymphatic glands.
It is difficult to explain how the pleural and peritoneal serous
membranes can be seriously invaded without the lung becoming affected,
though in point of fact such a state of things frequently exists.
Tuberculosis of the pleura without pulmonary lesions is suggested by
very obscure symptoms. The general signs consist in diminution of
appetite, loss of condition, tachycardia, elevation of temperature, and
progressive organic wasting. These are always present, though in
themselves they have no specific significance.
The local symptoms are still more vague. Percussion causes pain, and the
practitioner might at first suspect peripneumonia. The patient edges
away, and tries to avoid the application of the pleximeter hammer. Firm
pressure over the intercostal spaces sometimes causes struggling, and
produces indications of abnormal sensitiveness. There is generally
extensive partial dulness, sometimes complete dulness towards the lower
regions of the chest.
On auscultation the lung may reveal the different indications of chronic
pulmonary tuberculosis, or simply diminution of the respiratory murmur
at points, accompanied by crepitant, sibilant râles, and moist,
crackling sounds. As the anterior portions of the pleural sacs are most
commonly invaded, the anterior vena cava is compressed, causing some
difficulty in the return circulation, and producing venous pulse, which
may extend as high as the parotid gland; there is, however, no swelling
of the dewlap.
Respiration is frequent and difficult in consequence of adhesions
between the pleura and lungs, which are connected by bands of fibrous
tissue of varying extent. Coughing is rarely absent, and if the lung is
diseased may be followed by discharge containing numerous bacilli.
Otherwise the cough exhibits the pleuritic character, that is, it
remains slight, dry, paroxysmal, and painful. The pericardium may be
affected as well as the pleura; if the conditions occur simultaneously
the venous pulse in the jugulars will be particularly apparent.
The symptoms of tuberculous pericarditis are similar to those of
ordinary pericarditis, except that the exudation is less abundant; in a
word, the symptoms are those of rather trifling exudative pericarditis.
Tuberculosis of the peritoneum is frequently accompanied by that of the
pleura or the abdominal viscera. The lesions are localised on the
parietal peritoneum and epiploon, producing in time adhesions between
the viscera and walls of the peritoneal cavity, which affect the action
of the digestive organs, gradually causing interference with the
peristaltic movement both of the rumen and the intestines. The
stagnation of alimentary matter favours fermentation, so that the rumen
becomes permanently distended. The right flank also is swollen, and the
abdomen exhibits a change in shape similar to that in peritonism, which
is a constant symptom of tuberculous peritonitis.
As in the thorax, the tuberculous lesions seldom produce extensive
liquid exudation, so that ascites does not occur, but on palpation the
abdominal walls appear to have entirely lost their pliability and to be
unyielding and greatly thickened, a point which is the more remarkable
as the animals are thinner.
The wall of the abdomen is stiff, incapable of being depressed as in
ordinary subjects, and gives to the fingers the sensation of a thick
hard covering, through which the subjacent organs and their contents,
that is, the rumen, intestine and alimentary material, can no longer be
felt. This rigidity is always most marked in the lower abdominal region.
The digestive peristaltic movement can no longer be detected, and on
auscultation the normal sounds are manifestly much slower than usual.
TUBERCULOSIS OF LYMPHATIC GLANDS.
It might perhaps have seemed more logical to place tuberculosis of the
lymphatic glands at the commencement of these clinical divisions of
tuberculosis, as when tuberculous lesions, of whatever kind, occur in
the lung, pleura, abdomen, etc., the lymphatic glands in the
neighbourhood are invariably invaded. In such cases, however, the
lesions in question are not the dominant features.
Under this heading must be classed tuberculous lesions which, on the
contrary, affect the lymphatic glands in so marked a manner that lesions
in other organs may be regarded as secondary. This occurs somewhat
frequently, because at the present day there is a tendency to believe
that inoculation takes place mainly through the mucous membrane of the
pharynx, and thence extends towards the neighbouring lymphatic glands.
At any rate, it is unquestionable that tuberculosis of the lymphatic
glands may exist quite apart from any other lesion visible to the naked
eye.
Two forms are very common, tuberculosis of the retro-pharyngeal region
and of the neck, and tuberculosis of the mediastinal lymphatic glands.
=Tuberculosis of the Retro-pharyngeal Glands.=—In addition to the
retro-pharyngeal glands the cervical chain of lymphatic glands, the
subglossal, subatloid, preparotid, and even the prescapular lymphatic
glands and those at the entrance to the chest, may also be invaded more
or less.
This form of tuberculosis may remain latent for a long time, attention
being attracted to it only when deglutition is impeded and local
deformity becomes apparent.
Swelling of lymphatic glands resulting from tuberculous infection is
slow and progressive, differing entirely from that which accompanies
suppurative adenitis. The neighbouring connective tissue is certainly
somewhat thickened or infiltrated, but the glands themselves can always
be detected. The region of the gullet is enlarged, the depression
marginating the lower jaw is filled up, the subatloid space disappears,
the subglossal glands occupy the space beneath the tongue, and in cases
where the lesions are very pronounced the œsophagus and larynx may even
be pushed downwards.
[Illustration: $1]
Swallowing is difficult, in consequence of compression of the upper part
of the œsophagus, and, as the laryngeal nerves may be included in the
swelling, dyspnœa or roaring not uncommonly results.
By palpation with one or both hands it is easy to identify the glands
and detect enlargement, hardness and sensitiveness. In exceptional
instances the caseous masses they contain undergo softening and
conversion into purulent material.
When the cervical lymphatic glands are attacked the jugular furrows
disappear, and the whole of the pretracheal and lateral regions of the
neck exhibit doughy swellings.
These swellings are rarely symmetrical, a fact which admits of this
condition being distinguished from lesions due to lymphadenitis, without
examining the blood.
The prescapular glands are rarely attacked, but those at the entrance to
the chest, which may be found on either side of the trachea by passing
the fingers between the two first ribs, are frequently enlarged to the
size of a fowl’s egg.
=Tuberculosis of the Mediastinum.=—Whenever the lungs are much involved,
the bronchial glands are also invaded, though the glands of the anterior
and posterior mediastina may escape. On the other hand, the mediastinal
glands are sometimes much involved, whilst the lung remains intact.
The lymphatic glands, particularly those of the mediastinum, may be
enormously enlarged, and the various accidents which result are due as
much to mechanical interference with the functions of adjacent organs as
to the lesions themselves.
When the glands of the anterior mediastinum are affected, they cause
compression of the anterior vena cava, with stasis of blood in the
jugular vein and venous pulse, then compression of the œsophagus and
trachea, and of the nerves at the entrance to the chest, producing
difficulty in swallowing, respiration and circulation.
[Illustration: $1]
If, as often happens, the glands of the posterior mediastinum are
affected and greatly enlarged, they may involve the œsophagus and the
œsophageal nerves, interfere with deglutition and rumination, and thus
produce marked disturbance. The animals only swallow with difficulty,
and later rumination becomes impossible, the antiperistaltic movement
not being powerful enough to overcome the resistance. Soon after eating,
the patients exhibit tympanites, certainly only to a moderate extent,
but the swelling is long in disappearing. This tympanites is due to the
difficulty in eructation and to the impossibility of rumination. The
contents of the rumen pass slowly towards the intestine until the onset
of a fresh attack.
On account of digestive difficulties, the animals rapidly lose flesh,
just as though they were suffering from extensive visceral lesions.
TUBERCULOSIS OF THE DIGESTIVE TRACT.
Tuberculosis of the digestive tract is rarer than tuberculosis of the
lungs or lymphatic glands, and occurs in two well-differentiated
clinical forms, that is to say, tuberculosis of the buccal and
pharyngeal membrane and tuberculosis of the intestines. Tuberculosis of
the liver, which is less easily recognised, is indicated by signs of
dyspepsia.
=Bucco-Pharyngeal Tuberculosis.=—This may be primary or secondary, and
occurs in the form of local or general glossitis or superficial
ulcerative stomatitis.
In the former case the glossitis may be regarded as due to
actinomycosis; in the latter it can only be mistaken for simple
ulcerative stomatitis.
It is accompanied by difficulty in mastication, and still more, where
the pharynx is invaded, in deglutition; abundant frothy salivation in
feeding; sometimes by true spasm of the pharynx and rejection of
masticated balls of food.
Locally the buccal mucous membrane (cheeks, tongue, pillars of the
fauces, etc.) exhibit ulcerations, with festooned borders, in size
something between a florin and a five-shilling piece, covered with a
greyish-yellow, earthy-coloured exudation adhering firmly to the
subjacent parts. The margin of the ulceration is but slightly indurated,
and the tongue preserves its mobility, except in cases of general
deep-seated glossitis.
The condition may continue for weeks and months without improvement.
=Intestinal Tuberculosis.=—Tuberculous enteritis is always accompanied
by tuberculosis of the mesenteric glands and of the sublumbar lymphatic
chain. It is indicated at first by chronic tympanites and peritonism,
unaccompanied, however, by atony of the rumen; at a later period by
intermittent diarrhœa, which attains a maximum and is followed by
constipation. Finally, when there exist numerous intestinal ulcers, the
diarrhœa is profuse and intractable, the animals rapidly grow exhausted,
and the disease spreads to other organs with startling rapidity.
The food is ill-digested and the fæces have a repulsive odour, as has
also the gas which escapes from the rumen when it is punctured.
TUBERCULOSIS OF THE GENITAL ORGANS.
In males, tuberculosis may attack the testicle and neighbouring organs
and tissues; in females, the ovary, uterus, vagina, or udder.
Tuberculosis of the testicle is rare. Moussu appears only to have seen
one case, namely, in the boar. The disease produces specific vaginitis
and specific orchitis, the serous surfaces of the vaginal tunic becoming
adherent, and tubercles forming in the depths of the testicle, whilst in
time the testicle becomes the seat of fungoid growths.
Tuberculosis of neighbouring glands has only been observed in the case
of the prostate. Clinically it is distinguished by symptoms which
suggest difficulty in urination, and comprise frequent straining,
efforts to micturate, dysuria, etc. Examination by the rectum reveals
changes in the prostate, but affords no exact information as to their
nature.
Tuberculosis of the genital tract in the female is usually a delayed
complication of a preceding visceral tuberculosis, though it may occur
as a primary disease, in which case the lesions are localised about the
vulva or the vagina. Tuberculosis of the ovaries, Fallopian tubes, and
uterus is much more common than that of the two organs just mentioned.
It seems certain that the disease may be transmitted directly from the
male to the female by copulation, in cases where the male animal has a
lesion on the penis.
Tuberculosis of the vulva is rarer, and is indicated by swelling,
sclerotic changes, and the presence of tuberculous nodules, varying in
size between a lentil and a hazel-nut; after ulceration of these
growths, a thick yellowish pus containing the specific bacilli is
discharged.
Tuberculosis of the vagina is also indicated by hardening of the walls,
sclerous infiltration, and the presence of deep-seated tuberculous
nodules, which may or may not become ulcerated. It may follow uterine
tuberculosis, the discharge from the uterus continually soiling and at
length infecting the floor of the vagina. In such cases the lower wall
of the vagina is thickened and infiltrated to a greater extent than the
roof, and is sometimes intersected by transverse ulcerated suppurating
folds. Bacteriological examination reveals the presence of bacilli.
Tuberculous invasion of the ovaries, Fallopian tubes, and uterus is
externally indicated by signs of chronic metritis accompanied by a
purulent discharge, which may or may not be fœtid, but always possesses
special characteristics. The neck of the uterus is half open, and the
discharge is continuous. The pus is of a greyish-yellow colour,
ill-formed, grumous, or more frequently granular, and it sometimes
accumulates in large quantities in the depressions of the vagina.
Examination by means of the speculum is of great value in diagnosing
such lesions. On examining the parts through the rectum, the walls of
the uterus are found to be greatly thickened, sometimes indurated,
bosselated or totally deformed.
The Fallopian tubes and ovaries may have attained enormous dimensions,
and the normal anatomy of the parts is greatly altered both as regards
dimensions and relations.
[Illustration: $1]
The almost inevitable consequences of tuberculosis of the genital organs
are hypertrophy, induration or caseation of the subsacral and sublumbar
lymphatic glands.
=Udder.=—Tuberculosis of the udder may be primary or secondary. When the
infection is slight the results may escape notice for weeks or even
months, the patients appearing to suffer only from subacute or chronic
mammitis, while at the same time the milk preserves its ordinary
appearance. In time, however, the mammitis becomes aggravated, the
infected regions are enlarged, and the secretion becomes grumous,
serous, curdled, and of a yellowish colour, afterwards ceasing
altogether. In some cases one quarter only is attacked, though total
mammitis is more common.
These forms of tuberculous mammitis tend towards hypertrophy, local
hardening, and the formation of deeply-seated cavities containing pus,
the gland itself sometimes acquiring enormous dimensions. The
retro-mammary lymphatic glands are invaded even before the gland itself
is seriously attacked. For a longer or shorter time the udder may
externally appear healthy, although on manual examination these
lymphatic glands are found to be indurated and bosselated.
TUBERCULOSIS OF BONES AND ARTICULATIONS.
Tuberculosis of the bones is seen only in young animals, and chiefly
affects the vertebral column and the bones of the head. The limb bones
are attacked as a rule only in the vicinity of diseased articulations.
The vertebral lesions corresponding to those in Pott’s disease in human
beings are very difficult to discover before they produce complications,
such as depression of the spine, compression of the spinal cord,
paralysis, etc.
Lesions of the bones of the head or of the limbs are characterised by
local deformity, destruction of osseous tissue, invasion of surrounding
tissues, and by local symptoms peculiar to tumours originating in the
periosteum.
[Illustration: $1]
Tuberculosis of joints produces special symptoms resembling those seen
in the “white swellings” of man, that is, diffuse, œdematous, warm and
moderately painful swelling of adjacent parts, accompanied by lameness
of varying intensity. According to Guillebeau and Hess, many conditions
described as strain or rheumatic arthritis are really tuberculous in
character. They may remain stationary for a long time, or even recede
under treatment. As a rule, however, these forms of tuberculous
arthritis assume the fungoid type and prove incurable.
They are clinically distinguished from ordinary arthritis by the
enormous swelling, which involves the extremities and a portion of the
shafts of the bones. The adjacent muscles are chronically contracted,
and the diseased joint is held semi-flexed. In course of time, if the
patients are kept alive, abscess formation may occur, but this is seldom
seen in practice, because the animals are slaughtered.
TUBERCULOSIS OF THE BRAIN.
Tuberculosis of the nervous centres, localised either in the meninges or
the brain proper, may attack both young and old animals, not as a
primary condition, but as a sequel to visceral disease, which, however,
may have produced no outward indications, a fact that renders the
diagnosis extremely difficult.
When localised in the meninges, the disease produces the symptoms of
ordinary meningitis, general weakness, vacillating, staggering or
irregular gait, disturbed vision, variation in the size of the pupils,
difficulty in swallowing, muscular twitching, cramp of the muscles along
the upper margin of the neck, etc.
Tuberculosis of the brain proper seems more commonly to affect the
anterior convolutions and the depths of the frontal and temporal lobes.
It produces some of the symptoms of meningitis or symptoms suggestive of
the existence of cœnurosis, as, for instance, walking in circles,
lameness of central origin, without appreciable lesions of the limbs,
prolonged kneeling, disturbed vision, generalised attacks of epilepsy or
of Jackson’s epilepsy, spasm of the pharynx, general signs of
compression of the brain or cerebral dropsy, dulness, coma, etc.
[Illustration: $1]
In the absence of pulmonary lesions it is extremely difficult to arrive
at an exact diagnosis except after injection of tuberculin, for the
above symptoms very closely resemble those of cœnurosis, brain tumours,
and even tumours in the frontal sinuses.
TUBERCULOSIS OF THE SKIN.
Cutaneous tuberculosis is one of the rarest forms of the disease. It is
distinguished by the formation beneath the skin of little hardened
swellings varying in size between a hazel-nut and a walnut, and
containing caseous or calcareous material. These swellings have no
connection with the superficial lymphatic glands. They may be found
grouped together within certain areas, or distributed irregularly over
the whole body, particularly towards the base of the tail.
The condition may be mistaken for generalised sarcomatosis, from which,
however, it is readily distinguished by microscopic examination of the
contents of the swellings.
ACUTE TUBERCULOSIS—TUBERCULOUS SEPTICÆMIA.
However rapidly the above-described forms of tuberculosis may develop,
the disease as a whole is always of long duration, and continues for
months, or even for years. The development of these chronic forms may,
however, be interrupted by various influences which cause it to assume
an acute character, either for a time or continuously. Each intermittent
attack aggravates the condition of the patient, but gradually subsides,
with or without treatment. Continued attacks, however, rapidly lead to
death; they may be seen in animals previously unsuspected of any grave
disorder.
[Illustration: $1]
The dominant symptom is continuous fever, accompanied by signs of
disturbance of any or all of the chief bodily functions.
The temperature rises to 102° Fahr. (39° C.), or even to 104° or 105°
Fahr. (40° or 41° C.), with morning and evening remissions of some
hours. The respiration is accelerated. On auscultation it is often
difficult to discover signs of chronic tuberculosis. The lung is the
site of repeated congestive changes, resembling those of
broncho-pneumonia or contagious pleuro-pneumonia. The pleura and walls
of the chest become extremely sensitive, as in the last-named disease,
and the abdomen may exhibit signs of peritonism, as at the beginning of
acute peritonitis. The pulse rises to 80, 90, 100, or even 120 beats per
minute, and the urine contains albumen in notable quantities. This
condition continues for weeks without apparent diminution, the patients
refuse food, lose flesh with startling rapidity, and finally die of
exhaustion.
It would be impossible from these peculiarities alone to identify the
nature of the disease which causes such progressive organic wasting, as
the continued presence of fever prevents the use of tuberculin, but
fortunately the preliminary changes in the lungs, lymphatic glands,
genital tract, etc., are sufficient in most cases for the purposes of
diagnosis.
=Sheep, Goats, and Pigs.=—In the other domestic animals tuberculosis is
only of secondary importance to the practitioner.
It has been seen in the sheep and goat, but almost exclusively as the
result of experiment. It must be understood, however, that prolonged
cohabitation with diseased oxen or lengthened sojourn in contaminated
places may easily produce tuberculosis in the goat, though the sheep
continues to resist for a somewhat longer period.
Clinically such tuberculosis presents little interest on account of its
rarity.
The same remark applies to pigs; nevertheless, an entire herd may become
infected, and it may be necessary, after making a preliminary
post-mortem, to examine the other patients. All forms of the disease
occur in pigs, the lung being most frequently affected, but tuberculosis
also attacks the intestine, udder, lymphatic glands, joints, etc. The
pig, in fact, is extremely susceptible to this disease, whilst the sheep
is only subject to it in a comparatively trifling degree.
=Diagnosis.= The clinical manifestations of tuberculosis are so numerous
and so various that it is often an extremely hard task to form a
diagnosis. Without doubt detection is relatively easy in well-marked
forms, such as tuberculosis of the lungs, lymphatic glands and genital
apparatus, but even in such cases the symptoms must be reasonably
well-marked.
At first, unless the lesions produce externally visible signs, diagnosis
is impossible, and in the case of hidden forms, such as tuberculosis of
the serous membranes, mediastinum, intestine, testicle, etc., all that
can be done is to take into account the probabilities.