NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
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is evolved in the tissue, and is in part taken into the general circulation
by the capillaries and lymphatics; if only a small quantity of it remains
in the connective tissue the local accidents are insignificant; if much
passes into the blood, a tumor here and there may result; if much virus
remains in the subcutaneous tissue, a tumor is produced; when death
does not occur too rapidly symptomatic tumors appear, due to extravasa-
tions.
Intertracheal injection may give a mild form of the disease and
immunity. The microbes injected into the respiratory passages pass
from the infundibula into the vessels, traversing the pulmonary epithe-
lium and the vascular eudothelium. Attempts made to cause the disease
by gastric ingestion are generally unsuccessful. Occasionally the injection
of virus, intensified by methods which will be noted later on, has caused
virulent charbon with tumors in the ox. It is certain, then, that animals
may infect themselves by eating and drinking materials soiled with the
virus.
Charbon symptomatique may be transmitted by intra uterine conta-
gion when it attacks the mother during gestation; the mother, which
has gained immunity, appears capable of transmitting it to her off-
spring. Animals which contract the spontaneous disease may infect
themselves in various ways. The transmission occurs more particularly
by germs derived from the sick or their cadavers, which have been
distributed in external media and preserved intact. It may occur
through the intermediary of soiled instruments, etc., which may be
brought into contact with a wound on the skin or mucous membrane.
We have seen bulls thus inoculated during castration. It may occur by
the inhalation of dust mixed with germs. It may occur also by the in-
gestion of food and drink soiled with the virus.
When the microbes penetrate in sufficient quantity by a puncture or
wound of the skin or mucous membrane, the disease begins with local
lesions; a tumor forms. When the virus is introduced in small quanti-
ty into the connective tissue; when they gain the blood after inhalation
or ingestion, the disease commences with general symptoms, and sympto-
matic tumors appear at a later date. In certain countries where charbon
symptomatique is enzootic, it has appeared as though inundations favored
infection. The air may be contaminated by dust bearing the virus. It
is very fortunate, however, that animals which ingest, inhale or become
inoculated with the virus of this disease only fall dangerously ill, in
small percentage. This is because the microbes may be too weak, more
or less attenuated, so that animals infected with them are only attacked
by a mild form, and acquire immunity more or less complete.
B 2
20
Immunity.—Attenuation, recuperation, and exaltation of viru-
lence—Vaccination.—A non-fatal attack of the disease confers more or
less complete and durable immunity, and this is, if anything, more perma-
nent as the affection has been grave. Such a mild attack may be induced
by the inoculation of minimum doses of strong virus, by inoculating in cer-
tain regions (ear or extremity of the tail), by injection into the vein or the
trachea, by the use of attenuated virus or soluble substances obtained
from the microbe. Immunity may be heriditary, transmitted from
parent to offspring, and, lastly, animals may acquire it by spontaneous
infection with small quantities of, or attenuated, virus. The refractory
state of conferred or acquired immunity implies that the animals which
possess it are endowed with a bactericidal quality of their humors and a
peculiar condition of phagocytosis of their elements powerful enough to
destroy the microbes. All the elements of animals which are immune
appear to be endowed with bactericidal powers. Roger has observed
that the thigh of a vaccinated guinea pig does not form a suitable me-
dium for the development of the virus when inoculated and placed in an
incubator, whilst that of a non-vaccinated one, under similar conditions,
soon develops a tumor.
Attenuation of virulence.—Exposed to the influence of physical
or chemical agents, the microbes of charbon symptomatique may be
progressively deprived of their activity before being completely des-
troyed. It is certain that the microbes in the soil undergo more or less
rapid and important modifications according to its depth, composition,
and physical condition. It is said that virus in the superior layers of
the soil, where it does not undergo dessication, becomes rapidly attenua-
ted under the influence of light and air. On the contrary, virus deposited
at the depth of 1 metre or lower is preserved for a longer time. Gotti
has been able to communicate the disease with the washings of earth
from a depth of 0.40m. of a place where charbon symptomatique had
not shown itself for several years. Germs so preserved may be brought
to the surface by the same agents as have been mentioned under char-
bon.
When the microbes are cultivated in artificial media they may lose
their virulence more or less rapidly, passing through various phases of
attenuation, during which we may collect certain cultivations which may
be used as vaccines. However the experiments which have been pub-
lished are too few on this point, and we are hence inclined to be reserv-
ed. We cannot so far attach much weight to attenuation by means of
antiseptic substances.
Attenuation by heat merits some consideration. We have already
seen that it influences to a certain degree both the fresh and the dried
virus. By heating the fresh virus from 40 to 70 minutes at 65°C., we
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cause a certain amount of attenuation, which is evidenced by its action
on guinea pigs being lessened. By exposing it in a sealed tube to a
temperature of 70°C., for an hour and forty-five minutes, we may trans-
form it into a vaccine. Nuvoletti, by heating the virus in hermetically
sealed flasks at 35 to 38°C., for several months, has produced attenuation,
and rendered it vaccinal. Kitasato has conferred immunity on the guinea
pig by injecting a culture of fifteen days, and by the injection of the
virus which had been heated to 80°C., for thirty minutes. It is by the
action of heat upon the dessicated virus, however, that we obtain the
most uniform results. The temperature must be taken above 60°C. to
obtain any certain attenuation, and experience has demonstrated that we
should take it above 80°C. We obtain a very attenuated virus for
premier vaccine by heating to 100 to 104°, and a deuxieme vaccine
by heating to 90° to 94° ; leaving the virulent matter in the incubator
for seven hours, placing the material so attenuated in blotting paper and
in a dry dark case in the presence of some deliquescent material, under
which circumstances it is preserved for a year. Each vaccine is pulver-
ized in a special mortar, sifted and preserved as a powder. The virus
attenuated by heat, as has been indicated, does not transmit it to that
derived from it in the sick animal ; it regains noxious properties.
Kitt demonstrates that it is possible to confer immunity by one ino-
culation of dessicated virus which has been submitted to the action of
steam at 100°C.
Recuperation and augmentation of the virulence.—The viru-
lence of an attenuated virus may return to its original intensity, or even
become augmented. We may revive its pristine activity either by
cultivating it in animals very susceptible naturally or rendered so by
artificial means, by traumatism or by the action of some substance on it.
Thus, virus attenuated by seven hours beating at 100°C., which does not
destroy the adult guinea pig, but is still virulent for the young newly-
born pig, may be regenerated by inoculating it into this animal. Thus,
also, by inoculating large doses into adult animals we may destroy them,
and in this case we shall find that the microbes have regained their
virulence.
MM. Arloing and Cornevin have given back to an attenuated
virus its original virulence by leaving it for some hours in contact with
one-fifth solution of lactic acid: " It suffices to add lactic acid to the water
in which we dilute the virus and leave the water so acidulated in con-
tact for five or six hours. After this time, inoculation with the virus
previously attenuated communicates virulent charbon with certainty. "
Moreover, lactic acid intensifies the virulence of strong virus when it is
employed alone or in the following manner: " If we mix lactic acid with
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a small quantity of water to which has been added some very fermentes-
cible sugar and pour this into the virulent liquid thirty hours before
inoculation, we obtain a virus of maximum intensity."
We have, therefore, in lactic acid an agent which intensifies the viru-
lence of the microbe, and which is useful in demonstrating the presence
of the microbes in the soil.
MM. Nocard and Roux have verified the above conclusions, and
offer the following explanation of them: the virus attenuated by heat is
not properly speaking a truly attenuated virus, for it cannot reproduce
attenuated virus in culture ; dessication and heat in the preparation of
attenuated powder only leave the spores alive, render their power of ger-
mination and their action on the cells of the organism less; but anything
which diminishes the vitality of the tissues renders the development of
the virus easier, and seems to increase or restore its virulence. Lactic acid
does not in reality exalt the virus ; but, being injected along with it,
modifies the cells of the organism and so increases the receptivity by
diminishing the resistance. Experiment has shown that " a prolonged
contact of the acid with the virus is not necessary to regenerate its
virulence; the virus inoculated soon after its admixture with lactic acid
shows itself to be as active as the other. " Moreover, we may inject the
virus and the lactic acid solution separately, and the effect is the same.
Protective inoculation.—We can confer on animals immunity
from this disease, by inoculating the strong virus, the attenuated virus
or the soluble products secreted by the microbes.
As we have already seen, we may cause a mild form of the disease,
which is followed by immunity, by injecting a weak dose of the virus
into the connective tissue of certain regions, into a vein or the trachea,
or by injecting a very small dose into the connective tissue of any part.
None of these methods, however, are used in practice. With regard to
subcutaneous inoculation, there is too much danger. Subcutaneous in-
oculation at the extremity of the tail may be carried out with ease and
may succeed in conferring immunity without danger, but inoculation
with attenuated virus is preferable. As to intravenous and intertra-
cheal injection, there are so many difficulties attendant on their practice,
owing to the danger which must always exist of soiling the surround-
ing connective tissue, and thus, as we have already seen, inducing
virulent disease, that we are fain to discard this method (see Robertson
and Pemberthy Veterinary Journal, 1888). Robertson did not succeed
in obviating the attendant dangers in his experiments. In case, how-
ever, that it may be desired to practice it, we give the mode of pro-
cedure here. Either fresh or dessicated virus may be employed, and it
suffices to inoculate small quantities 3/10ths of a drop of fresh virus for the
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sheep three to ten drops for the ox. The dessicated virus is prepared as for
vaccines, which will be mentioned later on. We obtain the fresh virus
by killing a guinea pig with the disease, take a certain quantity of the
tumor, triturate in sterilized water, filter through calico, shake the
emulsion so obtained each time that we use it. If it be suspected that
the virus is mixed with septic microbes, we may treat it with sulphuric
acid, which rapidly destroys the latter, but has no action on the virus.
With regard to the method of inoculation, it is the same as that adopted
for pleuro. We have mentioned above the method of attenuation by
heat, which gives us two vaccines of unequal intensity, and which may be
used successively with a few days interval, commencing of course with
the weaker.
The virus, attenuated by heat, gives a mild form of the disease on
inoculation with a more or less considerable dose. To confer immunity on
animals without exposing them to grave attacks, we make two successive
inoculations—the first with virus attenuated by heating for seven hours
at 100°—104°C., and the second with virus heated for seven hours at
90°—94°C. These vaccines may be used for guinea pigs or for large or
small ruminants. The injections in oxen should be made into the sub-
cutaneous tissue at the end of the tail, towards the centre of the tuft, or
in the external surface of the ear as far as possible from the base.
The vaccines being in a state of powder must be subjected to certain
manipulations before injection. A quantity sufficient for the inoculation
of a certain number of animals, ten for example, is triturated in a mortar
with 5 C.C. of sterilized water gradually added; then filtered through
linen, which has been sterilized and moistened with sterilized water; we
thus obtain 5 C.C. of virulent emulsion, sufficient to inoculate ten
animals. The syringe (pravaz) is filled ½ cubic centimetre (or even
six to eight drops to animals under a year) is injected, shaking the
material between each injection to distribute the microbes uniformly
throughout the fluid.
Subcutaneous injection at the tip of the tail or in the ear is a most
simple operation.
The seat of inoculation is cleansed, the hair removed, and the exter-
nal face of the tail selected. The organ is seized in the left hand and
with the right the canula introduced piercing the skin obliquely and
the injection made; protective inoculations should be made preferably in
the end of winter or the beginning of spring, eight or ten days should
elapse between the inoculations. We may inoculate young oxen a few
months after weaning—one month according to Delamotte. We may
dispense with the inoculations when animals have been born or reared
in a country where the disease is enzootic. We vaccinate more especial-
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ly animals aged from six months to three years. There seems to be no
danger in inoculating pregnant females, but it is prudent to avoid it if
possible. Cows vaccinated whilst in calf may transmit immunity to
their calves; and the calves from mothers vaccinated sometime after
conception are more resistant than others.
The immunity resulting from inoculation appears to last about eighteen
months, and it is advisable to re-inoculate young animals after a year's
interval, whilst this is not necessary when the animals are vaccinated
when aged about two years.
In order to prove the efficacy of protective inoculations, we may in-
oculate vaccinated and control animals with virulent virus, and compare
the results. It will then be found that the vaccinated resist, whilst the
non-vaccinated do not. It may occasionally happen that a tumor devo-
lops in vaccinated animals, but it is seldom followed by death.
The effects of the preventive inoculations are mild. There is some-
times slight fever ; the local lesions consist of a hot, painful swelling,
which soon disappears. Sometimes an abscess forms, which may either
terminate simply or may lead to necrosis of the tip of the tail.
Occasionally, though rarely, attenuated virus may lead to virulent
charbon, but this fatal result does not occur more than once or twice in
a thousand animals, however it shows us how necessary it is for the
veterinarian to omit no precaution.
Since the year 1881 numerous proofs have been accumulated which
establish the economic value of preventive inoculation. The inoculations
with virus attenuated by heat have been adopted in a number of coun-
tries. They have given the most satisfactory results and have diminish-
ed the mortality in the various departments of France, in Switzerland,
the Tyrol, Germany, Belgium, Italy, Austria and America; everywhere,
thanks to protective inoculation, we have seen the mortality almost com-
pletely cease its ravages amongst the inoculated animals, whilst it has
continued in the non-inoculated.
M. Thomas has inaugurated a method of vaccination by the em-
ployment of threads impregnated with virus and passed as a seton be-
neath the skin of the tail. M. Darbot has thus described it.—
" This method, which has been in vogue in Haute Marne for five
years, under the auspices of the veterinary society of this department,
consists in placing at the extremity of the tail, through the tissues seve-
ral threads rolled together, methodically impregnated with attenuated
virus. The virus is renewed by passing it through the frog; attenua-
tion is obtained by heat, and the division of the doses with which the
threads are charged is effected by means of a specially constructed appa-
ratus. The inoculation is made with a simple suture needle by simp-
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ly passing the threads through the tissue. The method bears favorable
comparison with others, the accidents to which it gives rise are nil. It
is therefore safe, and the security is due to the fact that the virus is re-
generated in the frog, and does not become again exalted after attenuation.
Inoculation in minimum doses is absolutely certain, the virus being
deposited in a wound which cannot heal; owing to the presence of the
thread its multiplication is assured. One inoculation is sufficient. "
M. Eloire of Capelle adopted this method, but found seventeen
animals out of fifty-eight died; he therefore abandoned it, and counsels
others to do so.
M. Roux has succeeded in conferring immunity by injecting the
soluble substances secreted by the microbe.
When we inject 40C.C daily of a culture of charbon symptomatique
made in veal broth, and sterilized by heating for fifteen days at a tem-
perature of 115°C., or by filtration through porcelain, into the peritoneum
of a guinea pig, we confer immunity, even against 1/5th centimetre cube
of intensified virus, whilst control animals die from this injection. The
liquids filtered through porcelain appear more active than those heated
to 115°C. The serosity taken from an animal dead of the disease, fil-
tered through porcelain and injected into the guinea pig in doses of
20C.C., renders them ill, but does not kill them, moreover, we confer im-
munity on the guinea pig by a daily injection of 1C.C. of filtered
serosity for twelve days.
According to Strebel, Professor Kitt of Munich, not liking the tail
as a seat of the inoculation, made experimental inoculations into the
shoulder behind the extensors of the arm, with an energetic vaccine, and
noted that these were not followed by any untoward accidents. Seeing
the good results obtained, Suchanka, Palla and Schwaiger of the Duchy of
Salzbourg (1888) tried vaccination on forty-three animals with the second
vaccine of Lyon. In the year 1889 they inoculated thirty-three animals in
the shoulder ; in 1890, 1,176, one of which died four days afterwards. In
1891, 1,254 beasts were inoculated in the same way without any accident.
Out of 2,506 vaccinations made with strong virus on the side of the thorax,
one fatal case of charbon was noted, which result may be considered to
be very favourable when we take into consideration the fact that the
2,505 animals were immune, although they had only undergone one in-
oculation. Considering these encouraging results, and after consulting
with M. Arloing, Strebel began vaccinating in the region of the shoulder
in the spring of 1893, using a special syringe having a large bore needle.
He remarks as follows :—
" I inoculated twice at the shoulder 530 young cattle, 119 with the
first vaccine, 198 with the second, and 213 first with the first and then with
the second vaccine of MM. Arloing, Cornevin and Thomas. The total
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number of inoculations at the shoulder was 743. I vaccinated 729 animals
in front of the articulation of the left shoulder, eight behind the articu-
lation of the same side, and six in the skin covering the external face of
the scapula.
I had already vaccinated 370 subjects without the slightest accident,
the only lesions being the formation in some cases of an œdematous tumors,
and these results had given me faith and confidence in the method;
then the first accident occurred, one animal succumbed and another
followed. I modified my method slightly, and made 255 inoculations
more. I had been employing non-filtered vaccine; it was now filtered. "
Suchanka, Palla and Schwaiger, although they did not filter their
vaccine, only had one case of charbon S. out of 2,506 inoculations. Accord-
ing to Zimmermann 3,666 animals were vaccinated in the Corarlberg and
only eight died (0,25 per cent of the disease later on, but there was no
death from inoculation.
During the spring of 1892, 4,820 animals of the same country were
inoculated.
MM. Guillod of Etain and Sunon at Spincourt vaccinated 1,500
animals on the chest in the department of Meurthe-et-moselle without
any accident. One animal died later of the disease (Rec de med. vet).
Strebel concludes that, despite the two fatal cases, he shall continue
to vaccinate fearlessly with a slightly filtered emulsion. The advantages
of his method over others are that the operation is rapid and simple, it
may be made before, behind, or upon the shoulder. Forty to forty-five
animals may be vaccinated in the hour. It is not necessary to cut the
hair, nor to disinfect the seat of inoculation; the skin is soft; as soon as
the needle is removed, the wound closes at once, and nothing can get into
it. Reflux of the inoculated material does not take place. There is no
hæmorrhage. The accidents to which it gives rise are not half as
numerous as those following inoculation at the tail.
Out of 8,241 animals surviving the vaccination, ten only have subse-
quently been attacked with charbon, 0.12 per cent, whilst with the tail
method the losses were triple that percentage. Out of 2,241 animals,
inoculated with vaccine of Lyon only one succumbed.
Technique of Strebel's method.—The material is injected subcutane-
ously, care being taken to avoid wounding the flesh, and this is best effec-
ted by raising a fold of the skin between the fingers and then making the
injection. (Journal med. vet. et de zoot, 1893.)
Delamotte.—Contributes a paper to the Repertoire Veterinaire,
1893, on the above subject and adds further successes to the method.
Protective inoculation in Switzerland, Austria and Prussia —
Strebel gives the following details of preventive inoculations against this
disease.