particular poison by repeated doses of the same poison, recalls the
old proverb, "Seek your salve where you got your sore," and brings us
to a consideration of some of the primitive antecedents of a practice
which, at the present time, promises to bring about so profound a
revolution in the art of medicine. The modern system of inoculation
has, however, arisen quite without reference to such antecedents,
which latter were not based upon any scientific laws or
considerations, but owed their evolution to local customs and
experience handed down from age to age by tradition, and in many cases
preserved through a simple faith in the superstitions which surrounded
them.
To such a category must be added the curious superstitions indulged in
by the native population of Tunis regarding methods of preventing
hydrophobia in persons bitten by rabid animals. Dr. Loir refers to
these primitive ideas on the art of healing in a report of the work
carried out at the Anti-rabic Institute at Tunis, one of the many
centres for the prevention of rabies by Pasteur's method which have
been established in every quarter of the globe except Great Britain,
the inhabitants of this "great conservative island-Empire," as a
renowned foreign scientist describes it, still preferring a trip to
Paris to countenancing the establishment of an anti-rabic institute in
their own country. The Arab physicians in Tunis have from time
immemorial sought to specially identify themselves with cures for this
disease, which is so prevalent as to be a veritable scourge to the
country. A much-vaunted remedy advocated by the profession consists in
pounding up the charred head of a rabid dog with vinegar, and
administering an emulsion of the same to the patient. The dung of
camels is also highly prized as a remedy, as also the water of certain
wells which the simple faith of the natives has endowed with
supernatural curative properties. But the strangest prescription of
all consists in broth made from lambs a year old, to which is added a
peculiar kind of beetle, but in such a small quantity that the latter
ingredient only equals the weight of a grain of corn. This concoction
is given to the unfortunate patient twenty-three days after he has
been bitten. In the urine, according to the Arabian doctors, seven
small worms should be found which represent the embryos of dogs
engendered by the virus in the human body, and which when once got rid
of the patient recovers!
In the face of such crude traditions upheld with so much tenacity by
the native population, it is surprising that the Tunisian Anti-rabic
Institute has met with such a large measure of support in the shape of
applicants for admission, which, on an average, number over one
hundred annually. The mortality amongst those treated closely
approaches the satisfactory results obtained at the Paris Institute,
where the death-rate amounts to about 0·38 per cent. of the persons
treated.
There is perhaps no more interesting chapter in the history and
literature of medicine than might be compiled by searching out the
early uses of drugs and the primitive application of methods in the
art of healing, and tracing their connection, if possible, with the
practices which are in vogue at the present day. In the matter of
toxins and anti-toxins, or in respect to the modern theories of
preventive medicine, there would appear to be a curious link between
the methods based upon elaborate scientific inquiries and those which
arose through simple experience and expediency.
The idea of a poison, as the old proverb above tells us, being a
corrective for itself is no new idea, for we read how in ancient
times, for example, the Ophiogenes of the Hellespont were renowned for
their immunity to snake poison, and one account of them states
particularly that they fed upon serpents, and that to this diet they
probably owed their reputed magical art in withstanding the action of
serpent venom. Again, a traveller in Egypt, Hasselquist, tells us how
the serpent-charmers there eat serpents, making them into a kind of
broth, and that invariably before starting off to catch these reptiles
they partake of some of it.
In a paper by Mr. T. R. Rao on the Yánádés tribe of the Nellore
district, Madras Presidency, the author mentions that these strange
people have, amongst other characteristics, absolutely no fear in
catching cobras, which they draw out of their holes without any alarm
as to their fangs, and that they appear to protect themselves against
the effects of snake-bites by swallowing the poison-sacs of snakes.
Bruce describes how he saw a serpent-charmer in Cairo who allowed
himself to be bitten by a viper between the forefinger and the thumb,
and made no endeavour whatever to apply remedies, neither did he
exhibit the slightest anxiety as to the consequences. That this was no
trick, and that the viper was really possessed of all its deadly
faculties at the time it bit the man, was proved by the fact that a
pelican subsequently bitten by the same animal died in thirteen
minutes. Bruce also tells of a man who "with his naked hand took a
viper from a number of others lying at the bottom of a tub. He put it
on his head, then in his breast, and tied it about his neck like a
necklace. Next it was made to bite a hen, which died in a few minutes;
and, to complete the experiment, the man took it by the neck, and,
beginning at the tail, ate it as one does a carrot or a stick of
celery, without any seeming repugnance."
A most interesting account of snake-charmers is given by Drummond Hay,
in his book on _Western Barbary_, in which he relates his experiences
with some of these wonderful individuals belonging to the sect called
Eisowy. Members of this sect, he mentions, frequently handled
scorpions and poisonous reptiles without fear or hesitation, and they
were never attacked by them. He was present at one of their
exhibitions of feats with snakes in which they both allowed themselves
to be bitten and provoked the snake to bite them. The charmer thus
bitten then in his turn ate or chewed the reptile, which, he remarks,
writhing with pain, bit him in the neck and hands till it was actually
destroyed by the Eisowy's teeth.
In South Africa snake poison is actually taken as a protection against
snake-bites, and if we turn to the _Lancet_ of the year 1886, we shall
find a letter from Mr. Alfred Bolton stating that his curiosity had
been aroused by the fact that while in South Africa cattle and horses
frequently died from the effect of snake-bites, the natives themselves
seldom or never appeared to suffer any inconvenience from such
injuries other than would follow any accident which would set up local
inflammation. On inquiry he found that they were in the habit of
extracting the poison gland from the snake immediately it is killed,
squeezing it into their mouths and drinking the secretion, thereby
apparently acquiring absolute immunity from snake-bites. So impressed
was Mr. Bolton by what he observed that he adds: "I can no longer
refuse to believe in the efficacy of the snake virus itself as a
remedy against snake poison."
Savage tribes have learnt from bitter experience how to protect
themselves from snake-bites, and it is well known that they have a
method of inoculation which they employ with success. The Creoles of
Surinam use an ointment as a protection against snake-bites, which is
regarded as highly efficacious. It is reputed to consist principally
of the pounded head of a rattlesnake, which concoction would therefore
include the contents of the venom glands. This is then mixed with the
juices of a certain plant, which addition probably mitigates the
intensity of the venom by acting as a diluent. This substance is
generally applied by making an incision in the wrist or forearm and
rubbing it in, after which individuals thus treated appear to enjoy
security from the venom of snake-bites.
What applies to serpent venom would also appear to hold good in regard
to other poisons, such as that contained in the sting of a bee. This
poison is extraordinarily tenacious of its irritant properties, and,
unlike eel poison, retains its virulence even when exposed to high
temperatures.
An interesting memoir on the immunity of the bee-keeper from the
effects of bee poison was published a short time ago by Dr. Langer in
a German scientific journal. He issued a number of circulars with
questions to be answered, and sent these to more than a hundred
bee-keepers in different parts of the country, with the result that a
hundred and forty-four stated that they were now immune to bee poison,
nine having been fortunately endowed with a natural immunity to this
irritant, whilst only twenty-six out of the whole number applied to
stated that they were still susceptible.
This condition of immunity to bee poison is obtained after a varying
number of stings have been inflicted; in some cases thirty, at the
rate of from three to four a day, are sufficient to ensure freedom
from further discomfort, but the inoculations may have to be prolonged
up to one hundred stings to secure complete immunity.
In experiments carried out on animals this immunity to bee poison has
been also induced by repeated application of the irritant. It was
formerly generally supposed that the irritant nature of a bee's sting
was due to the presence of formic acid; but inasmuch as bee poison can
retain its poisonous character in spite of being submitted to heat,
which would effectually volatilise the formic acid present, this
assumption must be abandoned, and opinion is more inclined now to
regard this irritant substance as partaking of the nature of an
alkaloid.
Before closing this brief review of some of the most recent
discoveries which have been made in the domain of immunity, we must
mention some extremely suggestive and important researches on the
poison of tetanus, or lock-jaw, which have emanated from Dr. Roux's
laboratory at the Institut Pasteur in Paris.
It will perhaps be remembered that Pasteur, when working at
hydrophobia, experienced the greatest difficulty in exciting rabies in
animals with certainty, and that it was only when the fact of its
being a disease which essentially affects the nervous system of the
animal was taken into account that it occurred to him to cultivate the
virus in the medium for which it had seemingly the greatest affinity,
viz. the nervous tissue of an animal; it was only on taking this step
that he succeeded in invariably provoking rabies in the animals under
experiment.
In the case of tetanus we have another disease affecting the
nerve-centres of the body, and although many authentic cases have been
cited in which the treatment with anti-tetanic serum has been entirely
successful, a great many instances have occurred in which it has been
of no avail at all, more especially when the disease has obtained a
firm hold on its victim. Now Dr. Roux has not only been carrying out
experiments to ascertain what is the result of directly attacking, as
Pasteur did in the case of rabies, the nerve-centres of an animal with
the tetanus toxin, but he has also taken another and very important
step further, and has investigated, not only the action of the toxin,
but also that of the anti-toxin on the nerve-centres of an animal
suffering from tetanus.
In describing the cerebral inoculations which he has conducted on
animals, Dr. Roux points out that the operation, in itself, is
attended with no pain or even inconvenience to the animal in question,
that subsequently it eats with its usual appetite, and shows no signs
of discomfort.
First, as regards the infection of an animal with the tetanus virus
introduced directly into the brain, it has been found that very much
smaller quantities produce a fatal result than when subcutaneously
inoculated. Thus, a rabbit which received two cubic centimetres of the
poison under the skin took four days to succumb to tetanus, whilst
one-twentieth of the quantity inoculated into the brain sufficed to
kill another rabbit of the same size in less than twenty hours.
Another very instructive example of this susceptibility of the
nerve-centres for certain poisons is afforded in the case of rats
and the toxin of diphtheria. Rats possess a natural immunity from
this substance, and can successfully withstand a dose of diphtheria
poison introduced under the skin which would infallibly kill several
rabbits. This state of immunity, however, entirely disappears when
the toxin is brought directly in contact with nervous tissue, for
a very small quantity of diphtheria poison--insufficient to cause
under ordinary circumstances even a passing swelling at the seat of
inoculation--will, when introduced into the brain of a rat, kill the
animal.
Again, rabbits are generally credited with possessing high powers of
resisting the action of morphia, a large dose of this substance
introduced subcutaneously producing no result whatever. A cerebral
inoculation, however, of a minute quantity of morphia causes an
immediate reaction, and the animal, after remaining in a more or less
dazed condition for several hours, finally succumbs to this drug. Dr.
Roux is inclined to regard this difference in the susceptibility
exhibited by animals to one and the same poison as being due to a good
deal of the toxin, when subcutaneously introduced, failing to reach
the nerve-centres, it having been destroyed or arrested in the system
before it could attack them.
What is the nature of the subtle forces which may so beneficially
intervene between the toxin and its victim has long been a problem
which has excited the interest and ingenuity of some of the most
brilliant scientific authorities of the day, and it is one which, even
in the hands of men like Metchnikoff, is still awaiting a satisfactory
solution!
The important point was next approached by Dr. Roux as to whether an
animal, successfully trained to withstand large doses of the poison,
as ordinarily introduced, could also resist it when directly
inoculated into the brain. Is, in fact, the undoubted immunity to
tetanus poison which may be possessed by an animal due to the
nerve-centres having become insensible to this substance? The answer
to this question would appear to be in the negative, for animals
artificially protected from tetanus poison introduced under the skin
succumbed to a small dose inoculated direct into the brain, which
would otherwise have not produced even a slight passing tetanic
affection of the limb where the inoculation was made. Immense numbers
of experiments were made under varying conditions, but the result was
fully confirmed, showing that the nerve-centres had not acquired any
immunity to the poison, although the blood serum of the victims to
such cerebral inoculations was proven over and over again to be
endowed with strong protective properties against tetanus poison.
The endeavour was then made to, in Dr. Roux's words, "place the
anti-toxin where the toxin is working," and preserve the vital force
of the nervous tissue. To arrest tetanus by substituting cerebral for
subcutaneous inoculations of the anti-tetanic serum was the next feat
attempted. Several guinea-pigs and rabbits were inoculated
subcutaneously with virulent doses of tetanus poison sufficient to
kill them in about seventy hours; some were subsequently treated with
anti-toxic serum introduced in the ordinary way under the skin, whilst
others were inoculated with from six to seven drops of this protective
serum direct into the brain. The results were extraordinarily
successful. Although but a few drops of the anti-toxin were used for
the _cerebral_ inoculations, the animals survived the otherwise fatal
doses they had received of the toxin; whilst out of seventeen
guinea-pigs which received _subcutaneous_ inoculations of the
anti-toxin only two recovered, and the quantity of the anti-toxin
employed reached as much as from ten to twenty cubic centimetres in
some of the experiments, contrasting in a remarkable manner with the
few drops which sufficed in the case of the cerebral inoculations.
Dr. Roux sums up this splendid result in the following modest words:
"Il ne suffit pas de donner de l'anti-toxine, il faut la mettre au bon
endroit."
The significance and far-reaching application of this most important
discovery cannot easily be overestimated. Hitherto the preparation of
an anti-toxin has been the chief point considered, but Dr. Roux and
his able coadjutor, M. A. Borrel, have shown how great may be the
results which attend its method of administration, and have opened up
an entirely new direction for investigation.
Although the subject of immunity is not, as we have seen, by any means
wholly a latter-day creation, yet its approach and consideration from
a modern point of view, assisted by the resources and equipment
provided by modern scientific methods, justifiably entitles the
nineteenth century to claim it as its own discovery.
However brilliant and successful the labours may be of those who will
follow in the future, subsequent generations will know how to venerate
those great leaders of scientific thought, amongst whom we must rank
Pasteur, to whose genius the world owes so great a debt of gratitude,
and the vast extent of whose labours cannot be adequately measured at
the present day by reason of the restricted scientific horizon which
encircles public opinion in this country.
THE END
PLYMOUTH
WILLIAM BRENDON AND SON
PRINTERS
End of Project Gutenberg's Bacteria in Daily Life, by Mrs. Percy Frankland