conjectured. Direct inoculation on a sore by contact, by insects, by
harness, by accidents, etc. is an undoubted method. The sound cuticle
is probably an efficient barrier, since bacteria habitually inhabit,
without hurt, the surface and gland-ducts of the skin; yet the
entrance of these saprophytes through the shell and membranes of the
egg leaves a doubt as to the efficiency of the cuticular obstacle. The
mucous membranes are manifestly frequently penetrated by the parasite.
Hence the local affections in the mouth and throat (glossanthrax,
anthrax angina) and in the lungs (pulmonary anthrax). Cohn claims that
the gastric juice of Carnivora especially is destructive to the
anthrax poison, yet the constant recurrence of intestinal anthrax
(mycosis) seems to imply that the germs often escape destruction {934}
in the stomach. Pasteur supposes that anthrax-infected food is only
injurious when there are inoculable sores in the mouth or pharynx, but
it seems as if in that case the disease would be first shown at these
points and in the nearest lymphatic glands rather than in the bowels,
the rule for the inoculated anthrax being to develop first in the
tissues and thence to reach the blood-vessels through the lymphatics.
The anthrax poison expends its fatal energy especially on the blood
and blood-vessels. The bacilli in the blood use up the available
oxygen, so that the circulating liquid becomes venous, dark, and
unfitted for the maintenance of the normal functions of life. What is
even worse, the ability of the blood to absorb oxygen is greatly
impaired. In men and dogs suffering from anthrax the consumption of
oxygen was found to be reduced in one instance even by two-thirds,
probably in part by reason of the action of the chemical products of
the bacillus. A third condition constantly found is embolism of the
capillaries by the bacillus and the occurrence of local gangrene.
SYMPTOMS.--Anthrax shows itself in three principal forms: 1st, the
apoplectiform; 2d, anthrax fever without local external lesions; and
3d, external localized anthrax. The two last forms correspond in the
main to the acute and subacute forms.
The period of incubation varies according to the dose of the poison
and the receptivity of the animal. In some cases infection is at once
followed by illness. In these it is probably the chemical products
that produce the first effect, while the disease caused by the
propagation of the bacillus appears later should the animal survive.
Such incubation is shortest for the smaller animals (mice, rabbits,
guinea-pigs, cats), in which illness usually sets in in from
twenty-four to forty-eight hours. In sheep and goats incubation may be
extended to three or four days, while in horses and cattle it may last
a day longer.
The apoplectiform type attacks animals which a few minutes before
seemed in fine health, appetite, and spirits, striking them down as if
by lightning, and the victims struggle convulsively for some minutes,
expel blood perhaps by the nose or anus, and expire. In the less
suddenly fatal cases there may be muscular trembling, unsteady gait,
excited breathing, accelerated pulse, tumultuous heart's action,
bleeding from some natural orifice, and death in from one to several
hours. Occurring as these cases often do in summer, the sudden death
is probably hastened by insolation.
In anthrax fever or acute internal anthrax there is loss of appetite,
and, in ruminants, of rumination, suppression of milk, dulness,
languor, staring coat, or even a rigor, and thirst. Then follows the
hot stage, in which the temperature may rise to 106° or 107° F.; there
are acceleration of pulse and breathing, petechiæ or a brown or
yellowish tinge of the mucous membranes and white parts of the skin,
tenderness of the spine, often jerking or clonic spasms of the muscles
of the extremities, and much prostration and weakness, the patient
hanging back on the halter, leaning against a wall, or swaying when
made to move. The feces are usually more or less mingled with
blood-clots, or may be at once liquid and bloody. Bloody urine and the
discharge of blood from other natural channels are frequent. Some
cases are manifestly delirious, and in others the skin crackles on
being handled. Remissions are not uncommon, {935} during which the
animal remains dull and prostrate. As the disease advances and the
blood is robbed of its oxygen, the temperature descends below the
natural standard, great weakness and stupor set in, the pupils are
widely dilated, and death from asphyxia occurs in one or two days from
the onset.
In localized external anthrax the local swellings may be first seen.
There are usually some tenderness of the skin, erection of the hair,
and the formation of a little nodule, like a hazel-nut or walnut,
adherent to the deeper parts of the skin, firm and comparatively
painless even when cut. Sometimes the swelling is diffuse, with a
dropsical or erysipelatoid aspect, and crackles like parchment when
handled. Whether the affection attacks the tongue, the throat, or some
part of the head, body, or limbs, the tendency is to gangrene of the
part, and, if the subject survives long enough, to an extensive
sloughing and unhealthy sore. The sloughs and sores have either a
black sanguineous appearance or they are lardaceous and intermixed
with streaks of dark red. If fever is not present at the outset, it
sets in early, and passes through the same stages as in the acute
internal anthrax, the animals being suddenly plunged in prostration
and stupor, with dusky yellow or blood-stained mucous membranes,
dyspnoea, dilated pupils, convulsions, and death. On the mucous
membranes (gloss-anthrax, anthrax angina) the engorgement is usually
complicated with bullæ with red or yellow contents, and which on
bursting leave unsightly gangrenous ulcers. In all such cases the
morbid liquids of the swellings teem with bacilli.
MORBID ANATOMY.--The most characteristic changes are usually met with
in the blood. This is black, thick, tarry, uncoagulable or coagulates
only in loose diffluent clots, which are redissolved before squeezing
out the serum; the fibrin is diminished (often by two-thirds), the red
globules are not adherent in rouleaux, and are crenated and broken
down and the hæmatin diffused through the liquid, so that it stains
the hands or paper deeply; the white globules are increased, probably
by reason of the early irritation of the lymphatic glands and spleen
by the poison; and it reddens slowly and but slightly on exposure to
the air, and speedily passes into decomposition. The blood can
scarcely be made to flow in a full stream, but often trickles down the
hair and skin by reason of its thick, consistent character. The
microphytes above described are usually found in the blood, and always
in the affected tissues if examined just after death.
Next to the blood, the spleen presents the most constant lesions,
being enlarged (by one-third, one-half, or to double, triple or
quadruple its normal size) and gorged with blood (sometimes even to
rupture). The lymphatic glands, and especially those adjoining the
local anthrax swellings of the tissues, are always enlarged, marked
with petechiæ, friable, easily reduced to a pulp, and swarming with
bacilli and micrococci. Next to the glands of the affected parts the
central ones, the axillary, prepectoral, thoracic, sublumbar, and
abdominal, are the most constantly affected. The lymph is reddish and
opaque.
Decomposition sets in early, and the resulting gases cause a puffy,
emphysematous condition of the connective tissue. The fat and other
white tissues are dusky brown or yellow, and petechiated; the muscles
are soft, flabby, and dark red or brown, with occasional blood {936}
extravasations; the blood-vessels, especially the veins, and the right
heart are gorged with black, uncoagulable blood, and have their inner
coats blood-stained. The serous membranes present numerous petechiæ,
and contain more or less of a reddish serum. The intestines, and
sometimes the stomach, are dark red throughout, marked by petechiæ,
and are often the seat of thickening from sanguineous or transparent
colloid infiltration. The lesions are especially extensive on the
small intestines and rectum. The vagina and womb are also the frequent
seats of sanguineous infiltration. The liver and kidneys are enlarged,
congested, softened, and friable, and the ganglia of the sympathetic
are enlarged, congested, and softened. The swellings are of two kinds,
sanguineous and colloid. The former, when cut into, present one or
more loose clots of black blood or a grumous mass of blood-elements,
separating the tissues and often mixed with fetid gases. The colloid
exudations are glairy, semi-solid, jelly-like masses, infiltrating the
tissues. The tissues affected and the skin covering them are the seat
of bacterial embolism and gangrene, and there is no tendency to
suppuration. These products swarm with the specific microphytæ.
DIAGNOSIS.--The differential diagnosis of anthrax from other
affections due to the propagation of microzymes in the system is not
always easy--so much so that a variety of bacteridian and allied
diseases (septicæmia in its various forms, erysipelas, swine plague,
chicken cholera, poisoning by the micrococci of fungi, black quarter
from bacteria, milk sickness, and Texas fever) have been erroneously
confounded with this affection. These all show the same dusky or
cyanosed mucous membranes, disintegrating blood-globules, loose
blood-clots, petechiæ, blood-extravasations, sudden and great
prostration, and enlargement and congestion of the lymphatic glands or
spleen. In some of these the duration of incubation (in swine plague
six to fourteen days and in Texas fever one month) serves to
distinguish, while in the majority the microzyme is globular (Texas
fever, micrococcus of fungi-poisoning, chicken cholera); in swine
plague the cocci are arranged in pairs; in black quarter the microbe
is a refrangent ovoid, single or in chains of two or three and a
motile linear body with a refrangent nucleus in one end; and in milk
sickness the germ is a spirillum. The germs are far more likely to be
detected in the local lesions and lymphatic glands than in the blood.
The specific nature of the symptoms and lesions can usually be relied
on, but in cases of doubt the inoculation of a small animal (rabbit,
guinea-pig, sheep) will be a material guide.
PROGNOSIS.--True anthrax leads to a very high mortality. The
apoplectiform cases are fatal almost without exception; the acute
cases of anthrax fever in many outbreaks perish to the extent of 75 or
80 per cent., and the more tardy ones to the number of 50 per cent. In
a general outbreak the earlier cases are usually the most fatal, while
later, when the less susceptible animals are attacked, the mortality
is often decreased. Again, the mortality is often at once arrested by
the emigration of the herd to a more healthy soil, a large proportion
of those already attacked recovering.
PROPHYLAXIS.--In prophylaxis the soil demands the first attention. If
this is damp and calcareous or rich in organic matter, the remainder
of the herd should be at once removed to a drier and more porous soil,
where the germ is less likely to be preserved and increased. In an
{937} enzoötic in Livingston County, N.Y., in 1875, 40 bullocks out of
200 had perished in ten days, yet after removal to an adjacent dry
pasture and the use of antiseptics with the food and water the attacks
abruptly ceased and 48 out of 50 head already sick recovered. The
drainage of anthrax soils leads to a steady reduction of the poison,
favoring as it does the germination of the spores and the destruction
or modification of the germ. When drainage is impossible, the
mortality may be reduced by driving the stock to drier grounds during
the hot, dry season, by stabling them morning and night when the dews
are on the grass, also in wet times, when they are likely to pull up
the plants by the roots, or, better still, by cutting the fodder and
soiling the stock in stables or yards. Yet in all these cases the
germs will at intervals find access to the animals in the green food
or hay, so that badly infected soils must be secluded from live-stock,
and either be abandoned or devoted to other cultures. A point of the
very first importance is the safe disposal of the products and
carcases of the sick. These should be thoroughly burned, or, failing
this, deeply buried (4 feet) and the graves covered with coal tar and
fenced in from all other stock for from five to ten years.
Contaminated litter and fodder should share the same fate. Stables and
yards where the sick have been, and all vehicles and implements used
for them or their products, should be thoroughly disinfected. In the
epizoötic in Livingston County, above referred to, these measures seem
to have eradicated the disease in the course of six years, though the
land was neither drained nor subjected to cultivation, and the
dangerous meadows are now again pastured with impunity.
In the case of sick animals the greatest care is requisite to keep
them from common drinking- or feeding-troughs; to exclude all other
animals, even the smaller quadrupeds and birds, which may become the
bearers of the poison; to avoid the chance of the drainage of infected
excreta into other yards and pastures, and to carefully disinfect and
guard the human attendants against contamination. The sale of animals
out of an infected herd, and, above all, for the meat-market, and the
use of the milk or other products of such animals, until attested
sound, are highly reprehensible.
Finally, there are the different methods of protecting the system by
inoculation with modified virus. The first of these is that of
Burdon-Sanderson, Dugnid, and Greenfield, who in 1878 and 1879
inoculated six cattle with the blood of guinea-pigs dead of anthrax,
all of which survived except an old, emaciated, worn-out, and pregnant
cow, and all the survivors would only afterward contract anthrax in a
mild form. The anthrax blood of the guinea-pig inoculated on the sheep
proved fatal. The second mode is that of Pasteur, who cultivated the
anthrax-germ artificially in flasks of meat-infusion, and after the
nourishment in the latter had been used up left the bacilli to
degenerate until their virulence had been so far decreased that the
liquid could be safely inoculated on animals, so as to produce a mild
anthrax infection and thereafter secure immunity from this poison. For
all the larger domestic animals he found that the eighth day of the
culture sufficed, provided there had been no formation of spores; and
the method has now been applied on many scores of thousands of
domestic animals. Klein, however, has found that cultures in
pork-broth of the same age are invariably fatal to rodents, {938} and
that a guinea-pig which survived inoculation with culture a month old
did not possess immunity against fresh virus. The third method, that
of Toussaint, consists in heating the fresh virus, so as to lessen its
activity, and then inoculating it on the animals to be protected. He
found that a temperature of 55° C. (131° F.) maintained for one hour
rendered the virus non-fatal, without impairing its prophylactic
powers on animals inoculated. In spite of a partial failure at Alfort
from insufficient heating of the virus, the method has now been firmly
established as at once easy and effective.
The great value of these discoveries can hardly be overestimated, yet
it is to be feared that the éclat of their reception has led to a far
too general adoption of the methods. No one of the methods professes
to destroy the life of the bacillus nor to impair its power of
self-propagation. The bacillus, therefore, is likely to be planted in
the localities where it is being employed, and, if the soil is
favorable, to be perpetuated there. It follows also, from the
susceptibility of the bacillus to change under varying conditions of
life, that the modification impressed on it by the methods of Pasteur
and Toussaint may be reversed under a reverse state of the
environment, and that the harmless virus sown by our inoculators may
in favorable soils produce the more deadly types. The methods secure
the safety of the individual herd inoculated, at the expense of
planting in the pasture a seed most perilous to all future
uninoculated herds that may roam there. The only place for such
protective inoculations is on pastures already charged with the
anthrax bacillus, and from which that cannot be eradicated. On the
dry, healthful soils where the bacillus cannot survive the inoculation
is useless, while on the dense, damp, rich soils favorable to its
preservation, but as yet uninfected or nearly so, this inoculation is
but sowing deadly seed to secure a very temporary and questionable
advantage.
TREATMENT.--Bloodletting and laxatives have been largely used in the
treatment of anthrax, though both are mostly useless in acute cases,
their possible good effects being anticipated by the early death. When
of service at all, it is probably mainly in reducing that plethora
which serves often to enhance the virulence and severity of the
malady. Apart from these, the agents resorted to are more or less of
an antiseptic nature, and probably exert their action mainly on the
bacilli undergoing development near the surface of the skin or
intestinal mucous membrane. In extensive outbreaks I have had the best
results with the administration thrice daily of carbolic acid,
nitro-muriatic acid, or bichromate of potassium, and hypodermically of
iodide of potassium and sulphate of quinia. Alcoholic stimulants,
chlorate of potassium, and muriate of iron are equally indicated,
especially when the period of prostration has set in. If the local
anthrax can be detected when there is as yet but a hard nodule, there
should be no hesitation in cauterizing it to its depth and treating
the resulting sore and surrounding parts with tincture of iodine or
iodized phenol. After crucial incision the nodule may be treated with
powerful caustics (potassa, nitric acid, chloride of zinc), to be
followed by iodized phenol, with or without poultices or fomentations.
{939} Anthrax in Man (Malignant Pustule or Vesicle, Anthrax
Intestinalis, Mycosis Intestinalis).
Fournier in 1769 first traced the communicated anthrax of man to the
consumption of the flesh of diseased animals and the handling of their
wool. Until quite recently, however, the form which originated as a
local external affection was the only type recognized, while internal
anthrax was confounded with a multitude of other affections.
ETIOLOGY.--That anthrax in man is almost invariably derived from the
lower animals by infection is now undoubted, while for the direct
infection of man, as of animals, by the germs propagated in the soil,
there is no absolute proof. The latter mode of propagation has only
been recognized in the Herbivora, which are so much more exposed to
contamination from the soil; yet, abstractly, there is no reason to
suppose that man is less susceptible to the earth-grown bacillus than
to that produced in the animal, if only he were as frequently exposed
to its infection. The spontaneous development of anthrax apart from
the pre-existent bacillus in animals or soil is a chimera. The
principal modes of infection may be considered as direct and mediate.
Among the direct are included infection from handling the sick
animals, their carcases, their wool, hair, bristles, hides, fat, and
guts; the inoculation of physicians, surgeons, and nurses from their
patients; and the infection of men by the meat, milk, and cheese
eaten. As attested modes of mediate infection may be cited the
inoculation by insects (mosquitoes, bluebottles, and other
bloodsuckers), and the introduction by water into which anthrax
products have drained or been washed; there are also hypothetical
cases in which anthrax-germs from the earth have entered the system in
the air, drink, or food (raw vegetables). The direct inoculations are
especially common in certain classes (shepherds, farmers, butchers,
knackers, tanners, veterinarians, and workers in hides, hoofs,
glue-factories, fat-rendering works, in hair, wool, bristles, and
catgut, and in felting and paper-making). In such cases the disease
usually begins as a local one, and occurs on uncovered portions of the
body. Three such cases occurred in 1875 on one farm at Avon, N.Y.,
where the victims had assisted in burying forty dead cattle, and a
number of other similar instances can be adduced in different parts of
the same State, in one of which a physician was accidentally
inoculated in dressing a farmer's hand. Physicians whose practice
includes large tanneries become very familiar with the disease and
recognize it very readily.
Infection through food is much less frequent in men than in animals,
the process of cooking combining with the action of the gastric juice
in destroying the poison. Yet it is by no means unknown. The records
above given of infection in St. Domingo, Naples, and the Russian
steppes can be easily supplemented. Dr. Keith of Aberdeen, Scotland,
records the case of a family that suffered, two of them fatally, after
partaking of broth and meat which had been boiled for hours, one
member of the family (a vegetarian) having alone escaped. Infection
through milk, butter, and cheese is less common, the gravity of the
disease in animals leading to an early suppression of the mammary
secretion. In all such cases the infection enters through sores in the
mouth or from the bowels.
Those cases in which the bacillus enters the system with the inspired
{940} air are probably the least numerous. Yet the germ may reach the
lungs in fine dust, and then find in the delicate respiratory mucous
membrane the most accessible of all channels into the system.
The proportion of men affected is much greater than that of women and
children, doubtless by reason of their greater exposure to infection,
and, as in the lower animals, the summer months are most productive of
anthrax. The susceptibility of the human race appears to be less than
that of the Herbivora, and doubtless varies, as in these animals, with
the nature of the food. It is at least temporarily exhausted by a
first attack, though in exceptional cases and under a strong dose of
the poison a man may be affected a second time.
SYMPTOMS.--Symptoms usually set in within twenty-four hours after
inoculation of the poison, though it is alleged that the incubation
may be extended to twelve or fourteen days. Itching draws attention to
a small red spot like a mosquito bite, but with a black central point.
This speedily increases to a small rounded swelling (papule), and in
fifteen hours is surmounted by a minute vesicle with dark-red or
bluish contents. From the size of a millet-seed this increases to that
of a pea, and in thirty hours bursts spontaneously or under friction
and forms a dark-red, indurated, comparatively painless nodule (parent
nucleus, Virchow). The adjacent skin shows a swollen areola livid and
red, on which there appear vesicles similar to the first, which pass
through the same stages, burst, and leave a livid, hard, or doughy
gangrenous surface. By this time the surrounding skin is red, shining,
and puffy, and the disease continues to spread by the same method of
extension. The diseased part now becomes the centre of an oedematous
swelling which may invade the entire arm, face, or neck, and is
attended with more or less constitutional symptoms. The affected part
may be cold or hot, and it may show the red lines of lymphangitis and
the swelling of the adjacent lymphatic glands.